(gift  at 


CLASS 

ACC_ 


GIFT  OF 
BOHEMIAN  CLUB 


THE   AMATEUR 
TELESCOPIST'S   HANDBOOK 


THE    AMATEUR 


TELESCOPIST'S  HANDBOOK 


BY 


FRANK   M.  GIBSON,  PH.D.,  LL.B. 


NEW  YORK 

LONGMANS,  GREEN,  AND  CO. 

15  EAST  SIXTEENTH  STREET 
1894 


COPYRIGHT,  1893,  BY 
LONGMANS,   GREEN,    AND    CO. 


1,  173  Macdougal  Street,  New  York 


r 


PR^ESIDI,  PROFESSORIBUS  GUBERNATORIBUSQUE 

COLLEGII  SANCTI  JOHANNIS, 

ANNAPOLE,    IN    TERRA  -  MARLE, 

HONORIS  AB  EIS  DONATI 

MEMOR, 

HOC  OPUSCULUM  DEDICAVIT 
SCRIPTOR. 


701032 


"THE  works  and  design  of  the  Omnipotent  Creator  are  inscru- 
table to  the  most  brilliant  human  intellect;  yet  enough  is  revealed, 
both  with  regard  to  the  wondrous  universe  and  our  own  mental 
capacity,  to  convince  the  reflecting  mind  that  it  is  a  mark  of  devotion 
which  we  owe  to  our  Maker  to  study  with  earnestness  the  beautiful 
and  harmonious  works  around  us,  however  their  immensity  may  at  first 
bewilder  us.  He  who  zealously  applies  himself  will  verify  the  sacred 
promise,  'Those  who  seek  shall  find.'  In  worldly  pursuits  a  long 
novitiate  is  devoted  to  acquire  the  imperfect  concoctions  of  man;  how 
much  more  is  due  to  catch  a  glimpse  of  the  imperishable  laws  of  the 
CREATOR  !" — ADMIRAL  WILLIAM  HENRY  SMYTH. 


PREFACE. 

THIS  little  book  is  offered  to  amateurs  in  astronomy  in 
the  belief  that  it  fills  a  want  as  yet  unsupplied. 

For  the  possessors  of  equatorially  mounted  telescopes 
of  an  aperture  exceeding  three  or  four  inches,  efficient 
guides  are  already  in  existence.  Smyth's  Cycle  of  Celes- 
tial Objects  and  Webb's  Celestial  Objects  for  Common  Tele- 
scopes fulfil  almost  every  requirement  of  such  observers. 
But  for  the  far  larger  number  of  students  of  astronomy 
whose  instrumental  equipment  does  not  go  beyond  a  two 
or  three-inch  altazimuth,  these  admirable  works  are  to  a 
considerable  extent  unsuited.  The  worker  with  an  equa- 
torial can  quickly  and  easily  direct  his  telescope  to  any 
object  described  in  those  mines  of  celestial  wealth  ;  but 
for  his  humbler  brother  there  is  no  resource  but  to  labo- 
riously locate  the  given  star  or  nebula  on  a  map,  note  its 
position  with  reference  to  other  objects,  and  then  search 
for  it  with  the  altazimuth.  Moreover,  these  immense  col- 
lections of  celestial  objects  contain  a  very  large  number 
of  bodies  which  are  hopelessly  beyond  the  reach  of  a 
small  telescope  ;  and  the  novice  knows  not  which  among 
them  may  be  expected  to  reveal  themselves  by  the  assist- 
ance of  his  little  instrument,  and  is  at  a  loss  where  to 
begin  his  scrutiny  of  the  heavens.  If  all  this  work  could 
be  done  for  him  ;  if  a  selection  could  be  made  of  such 
objects  as  are  within  the  powers  of,  at  most,  a  three-inch 
telescope,  and  the  location  of  each  of  them  be  concisely 
and  yet  fully  described  with  reference  to  objects  visible 


X  PREFACE. 

to  the  unaided  eye,  a  vast  quantity  of  uncertainty,  difficulty, 
and  labor  would  be  cleared  out  of  the  student's  path. 
And  if,  in  addition  to  this,  a  method  could  be  provided 
by  which  the  use  of  a  map  by  lantern-light  could  be 
entirely  dispensed  with,  and  the  position  of  every  star 
used  in  locating  others  could  be  ascertained  almost  at  a 
glance,  it  is  very  evident  that  the  drawbacks  and  difficul- 
ties encountered  by  the  amateur  observer  would  be  greatly 
modified,  if  not  in  the  main  removed. 

Precisely  this  is  what  has  been  done  in  the  catalogue  of 
between  four  and  five  hundred  celestial  objects  contained 
in  this  book  ;  and  upon  this  fact  is  based  the  author's 
belief  that  the  Handbook  will  fill  a  want  in  this  field. 

That  portion  of  the  book  which  treats  of  the  principles, 
construction,  care,  and  use  of  the  Telescope  is  drawn  from 
many  sources,  and  contains,  it  is  believed,  more  practical 
information  upon  the  subject  than  any  other  one  volume 
treating  of  this  instrument.  A  certain  knowledge  of  as- 
tronomy on  the  reader's  part  is  assumed  ;  but  not  more 
than  can  be  obtained  from  any  primer  of  the  science. 

The  illustrations  are  limited  to  such  as  are  necessary  to 
convey  essential  information,  and  it  will  be  noticed  that 
no  attempt  has  been  made  to  give  any  of  the  diagrams  of 
double  stars  which  are  so  common  in  books  upon  this 
subject  prepared  for  amateurs.  Even  if  a  pair  of  dead- 
white  disks  on  a  black  ground  could  really  represent  the 
glittering  and  twinkling  stars,  they  would  not  serve  the 
purpose  which  is  usually  assigned  for  their  existence, 
namely,  to  give  the  student  an  idea  where  to  look  for  the 
companion  of  the  star  represented.  For  the  apparent 
relative  positions  of  the  star  and  its  comes  change  with 
the  successive  positions  of  the  object  in  its  course  across 
the  sky  ;  and  as  these  diagrams  usually  represent  the  rel- 


PREFACE.  XI 

ative  positions  of  the  components  when  the  star  is  on 
the  meridian,  they  would  be  useless  for  the  purpose 
assigned  when  it  was  at  any  distance  from  that  line. 

No  attempt  has  been  made  to  treat  of  the  Reflecting 
Telescope.  This  instrument  is  but  little  known  in  Amer- 
ica, although  it  must  some  day  come  into  favor  in  this 
country,  as  it  has  always  been  in  England,  especially 
since  the  introduction  of  the  silvered-glass  speculum, 
since  its  cheapness,  in  comparison  with  refractors  of  cor- 
responding aperture,  makes  it,  in  one  sense,  preeminently 
the  amateur's  telescope.  Should  a  future  edition  of  this 
Handbook  ever  be  called  for,  some  space  may  be  devoted 
to  the  Reflector. 

In  conclusion,  the  author  trusts  that  this  little  work 
may  prove  a  helpful  and  pleasant  companion  to  amateur 
astronomers  in  the  study  of  the  sublimest  of  the  physical 
sciences  and  the  use  of  the  noblest  of  optical  instruments. 

WASHINGTON,  D.  C., 
November^  1893. 


CONTENTS. 

PAGE 

PREFACE ix 

CHAPTER        I.  THE     TELESCOPE:     ITS    PRINCIPLES    AND 

POWERS i 

"  II.  TESTING  THE  OBJECT  GLASS. — EYEPIECES. 

— TUBES 16 

"             III.  THE  STAND 28 

"              IV.  ACCESSORIES  OF  THE  TELESCOPE 39 

"                V.  THE  CARE  OF  THE  TELESCOPE. 42 

VI.  THE  USE  OF  THE  TELESCOPE 45 

VII.  OBSERVATION. — STARS,  NEBULAE,  THE  SUN 

AND  MOON 52 

14          VIII.  OBSERVATION,  CONTINUED. — THE  PLANETS.  66 
**             IX.  PRICES  OF  TELESCOPES  AND  THEIR  ACCES- 
SORIES   74 

CELESTIAL  OBJECTS: 

ALIGNMENT  STARS 83 

A   DESCRIPTIVE   CATALOGUE  OF   FOUR    HUNDRED   AND 

SIXTY-EIGHT  CELESTIAL  OBJECTS 90 


THE 
AMATEUR  TELESCOPIST'S  HANDBOOK, 


CHAPTER   I. 

THE    TELESCOPE  I     ITS    PRINCIPLES    AND    POWERS. 

AN  opportunity  to  examine  celestial  objects  by  means 
of  a  telescope  is  one  which  is  so  eagerly  embraced  by 
almost  all  classes  of  people  as  to  indicate  that  telescopic 
astronomy  possesses  a  charm  which  should  lead  to  its  ex- 
tensive cultivation  ;  but  the  efforts  of  writers  on  this  sub- 
ject have  been  comparatively  unsuccessful  in  persuading 
students  of  natural  science  to  believe  that  a  small  tele- 
scope is  capable  of  gratifying,  in  any  real  sense,  the  taste 
for  these  fascinating  pursuits.  The  popular  idea  of  the 
telescope  is  of  a  huge  and  costly  instrument,  the  posses- 
sion of  which  must  necessarily  be  limited  to  educational 
institutions,  public  observatories,  and  wealthy  amateurs  ; 
and  the  fact  that  most  of  the  work  of  modern  astronomy 
is  done  by  such  instruments  serves  to  confirm  this  impres- 
sion. The  monster  reflectors  of  Herschel,  Rosse,  and 
Lassell  ;  the  colossal  refractors  of  Mount  Hamilton,  Chi- 
cago, and  Washington,  are  the  instruments  suggested  to 
the  average  mind  by  the  word  telescope;  and  a  diminutive 
tube  of  two  or  three  inches  aperture  is  neglected  and  dis- 
dained as  incapable  of  doing  aught  but  tantalize  the 
student  who  is  unable  to  procure  anything  better.  And 
I  i 


2  THE'  AMATEUR.  .T^LESCOPIST's    HANDBOOK. 

thfcn,  When  the  'would-be  possessor  of  a  telescope  comes  to 
examine  price  lists,  he  is  apt  to  stand  aghast  at  the  man- 
ner in  which  the  cost  of  object  glasses  advances  with  every 
half  inch  of  aperture  ;  and  it  is  only  too  probable  that  he 
will  surrender  the  idea  of  surveying  the  heavens  through 
a  glass  of  his  own. 

The  catalogues  of  celestial  objects  given  in  this  book 
should  be,  and  the  author  hopes  will  be,  an  effectual 
refutation  of  the  fancy  that  nothing  can  be  done  with  a 
small  telescope.  There  is  scarcely  an  object  contained  in 
them  which  is  not  fairly  within  the  compass  of  a  good  three- 
inch  achromatic.  The  exceptions  to  and  modifications 
of  this  statement  will  appear  in  their  proper  places  ;  but 
the  reader  is  assured  of  the  correctness  of  the  general  rule. 

There  is  a  tendency  in  certain  quarters  to  encourage 
the  amateur  astronomer  provided  he  wishes  to  do  work 
of  value  to  the  science,  but  to  speak  with  contempt  of 
mere  "star-gazing."  This  tendency  is  exhibited  in  more 
than  one  book  prepared  for  the  use  of  astronomical  ama- 
teurs, and  has  served  to  discourage  more  than  one  student 
who  was  unable  to  provide  himself  with  the  means  for 
doing  serious  astronomical  work,  or  to  acquire  the  neces- 
sary skill  in  using  them. 

Now,  it  might  as  well  be  stated  at  once  that  there  is 
scarcely  a  possibility  in  these  days  that  an  amateur  with 
a  small  altazimuth  telescope  can  accomplish  any  work  of 
scientific  value.  There  are,  indeed,  certain  fields  open  to 
him — e.g.,  he  may  observe  occultations  by  the  aid  of  a 
good  chronometer,  and  with  skill  and  care  may  thus  make 
some  contribution  toward  the  improvement  of  the  lunar 
theory  ;  *  but  even  assuming  that  he  possesses  a  chronom- 

*  Noble. 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  3 

eter  and  the  means  for  accurately  regulating  it,  work  of 
this  kind  is  already  being  done  by  accomplished  astrono- 
mers provided  with  the  most  perfect  instruments  which 
modern  skill  can  construct.  So  of  every  other  branch  of 
telescopic  astronomy.  In  earlier  days,  when  astronomical 
instruments  were  less  perfect,  professional  astronomers 
less  numerous,  and  the  magnificent  observatories  of 
modern  times  as  yet  unknown,  the  amateur  with  his  little 
telescope  might  be  a  distinguished  and  valued  co-laborer 
with  the  professional  with  his  not  very  much  larger  instru- 
ment. That  day  is  past  ;  and  it  is  most  likely  that  the 
small  telescope  has  done  all  of  which  it  is  capable  in 
the  way  of  original  scientific  work. 

But  surely  what  remains  within  the  power  of  this  humble 
little  member  of  the  mighty  family  of  telescopes  is  not  to 
be  despised.  To  merely  look  with  delight  and  wonder 
upon  the  twin  glitterings  of  the  double  stars,  the  gorgeous 
splendor  of  the  clusters,  the  pale  glow  of  the  nebulae ; 
to  scan  the  wild  scenery  of  the  moon  ;  to  watch  the  huge 
spots  drifting  across  the  sun  ;  to  follow  the  satellites  of 
Jupiter  as  they  circle  about  the  giant  planet ;  to  marvel  at 
Saturn  with  his  "wondrous  rings  "  ;  to  wait  and  watch  for 
the  startling  phenomena  of  occultations  and  eclipses  ;  and 
through  all  this  to  see  the  working  of  the  majestic  and 
glorious  laws  of  the  universe — this  is  not  to  be  set  aside 
as  worthless.  On  the  contrary,  the  mere  "  star-gazer  " 
will  find  a  never-failing  pleasure  in  the  contemplation  of 
these  stupendous  objects  ;  and  even  though  he  may  ac- 
complish nothing  for  science,  he  will  enjoy  the  most  re- 
fined, elegant,  and  fascinating  of  all  scientific  recreations. 

The  history  of  the  refracting  telescope  divides  itself 
into  three  periods  :  that  of  the  Galilean  telescope  ;  that 


4  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

of  the  Astronomical  telescope,  strictly  so  called  ;  and  that 
of  the  Achromatic.  While  it  is  not  within  my  purpose  to 
give  an  elaborate  account  of  the  optical  principles  in- 
volved in  these  instruments,  a  brief  explanation  of  them 
must  necessarily  be  introduced  as  highly  important  to  the 
telescopist. 

The  telescope,  as  invented  (in  all  probability)  by  Jan- 
sen  and  Lippersheim,  two  spectacle-makers  of  Middle- 
burg,  Holland,  and  improved  by  Galileo,  consists  of  a 
double  convex  lens  placed  at  one  end  of  a  tube  shorter 
than  the  focal  length  of  the  glass,  at  the  other  end  of 
which  is  fixed  a  double  concave  lens.  The  rays  of  light 
from  any  object  passing  through  the  convex  lens  are  in- 


FIG.  i. 

tercepted  by  the  concave  lens  before  the  image  can  be 
formed,  and  converted  into  parallel  rays  which  enter  the 
eye  of  the  observer  applied  to  the  latter  lens. 

This  instrument,  which  in  the  hands  of  Galileo  opened 
the  magnificent  career  of  modern  practical  astronomy,  is 
now,  by  the  irony  of  fate,  known  as  the  non-astronomical 
telescope.  It  still  serves  a  useful  purpose  in  the  opera- 
glass  ;  but  it  was  soon  cashiered  from  the  service  of 
astronomy  on  account  of  several  serious  and  radical 
defects.  The  first  of  these  defects  is  that  the  full  illumi- 
nating power  of  the  telescope  is  not  made  available.  A 
comparatively  small  number  of  the  rays  received  by  the 
convex  object  glass  are  transmitted  through  the  concave 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  5 

eye-lens  ;  and  if  we  use  an  eye-lens  of  shorter  focus,  and 
nearer  the  object  glass,  it  intercepts  more  of  the  rays,  to 
be  sure,  but  there  is  no  point  of  the  eye-lens  at  which  the 
eye  would  receive  pencils  of  light  emanating  from  any 
considerable  portion  of  the  object.  Mr.  Proctor  *  com- 
pares the  difference  to  that  between  looking  through  the 
small  end  of  a  cone-shaped  roll  of  paper,  and  looking 
through  the  large  end.  In  the  first  case  the  eye  sees  at 
once  all  that  is  to  be  seen  through  the  roll  (supposed 
fixed  in  position),  and  in  the  latter  the  eye  may  be  moved 
about  so  as  to  command  the  same  range  of  view,  but  at 
any  instant  sees  over  a  much  smaller  range. 

The  fact  that  in  a  Galilean  telescope  the  size  of  the  field 
of  view  is  dependent  upon  the  size  of  the  object  glass  is  a 
defect,  and  so  is  the  fact  that  any  scratches,  marks,  or 
partial  coverings  placed  upon  the  object  glass  are  visible 
on  looking  through  the  telescope  ;  but  the  great  defect  of 
this  instrument  lies  in  the  fact  that  in  the  Galilean  tele- 
scope no  real  image  is  formed,  owing  to  the  interception 
of  the  collected  rays  by  the  eye-lens  before  they  come  to 
a  focus  at  all.  Since,  then,  no  actual  image  exists,  it  is 
impossible  to  apply  any  measurements  to  it — a  well-nigh 
fatal  fault  from  an  astronomical  standpoint. 


FIG.  2. 

The  astronomical  telescope,  in  its  primitive  form,  consists 
*of  a  double  convex  lens  which  forms  an  inverted  image  of 

*  Half-hours  with  the  Telescope,  p.  8. 


6  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

the  object  under  examination,  and  a  smaller  double  con- 
vex lens  which  magnifies  the  image. 

The  rays  of  light  falling  through  the  object  glass  are  re- 
fracted to  a  focus  in  the  tube,  and  the  image  thus  formed 
is  magnified  by  the  small  lens  at  the  eye-end.  By  this 
arrangement  of  lenses  the  characteristic  defects  of  the 
Galilean  telescope  are  avoided.  The  size  of  the  field  of 
view  is  not  dependent  upon  the  size  of  the  object  glass. 
Scratches  or  marks  on  the  object  glass  are  not  visible  in 
the  telescope,  but  only  cause  a  certain  loss  of  light,  so 
that  a  portion  of  the  object  glass  may  be  covered  over, 
either  at  the  centre  or  at  the  edges,  for  certain  purposes, 
without  the  covering  object  being  visible,  and  the  whole 
of  the  light  transmitted  by  the  object  glass  becomes 
available.  Moreover,  the  image,  being  real  and  not 
merely  virtual,  may  be  readily  subjected  to  measurement, 
either  angular  or  linear ;  a  circumstance  which  alone 
would  make  this  instrument  preeminently  the  astronomi- 
cal telescope. 

But  this  primitive  telescope  has  two  most  serious  de- 
fects of  its  own  which,  if  not  removed  or  greatly  modi- 
fied, would  have  caused  it  to  remain  forever  a  clumsy  and 
imperfect  contrivance.  These  are  known  as  chromatic 
aberration  and  spherical  aberration*  The  first  of  these  is 
due  to  the  unequal  refrangibility  of  the  different  colors  of 
the  spectrum.  The  image  of  an  object  thus  does  not  lie 
in  a  flat  field  perpendicular  to  the  optical  axis  of  the  tel- 
escope (i.e.,  a  line  drawn  from  the  centre  of  the  objective 
to  that  of  the  eye-lens),  but  is  in  reality  divided  into  a 

*  I  omit  all  reference  to  the  curvature  of  the  image,  as  this  defect 
is  of  no  importance,  in  practice,  and  the  above  discussion  is  merely 
elementary. 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  7 

number  of  images  of  different  colors  lying  one  behind  the 
other  in  the  optical  axis.  Accordingly,  when  the  eye- 
lens  is  set  so  as  to  magnify  one  of  these  images,  a  colored 
fringe  due  to  the  other  images,  enlarged  by  being  out  of 
focus,  surrounds  the  image  under  examination.  The 
other  defect,  that  of  spherical  aberration,  is  due  to  the 
fact  that  the  rays  transmitted  through  the  outer  portions 
of  a  double  convex  lens  are  brought  to  a  focus  nearer  the 
lens  than  those  transmitted  through  the  centre. 

The  correction  of  these  faults  was  for  more  than  a  hun- 
dred years  the  great  desideratum  in  practical  astronomy. 
An  effort  was  made  to  remedy  them,  and  with  some  suc- 
cess, by  grinding  lenses  of  enormous  focal  length,  which 
were  elevated  upon  a  pole  and  provided  with  mechanical 
appliances  by  which  the  observer  could  direct  them  to 
different  parts  of  the  heavens,  and  examine  the  images 
formed  by  them  with  an  eye  lens.  One  of  these,  now  in 
the  possession  of  the  Royal  Astronomical  Society,  was 
made  by  Huygens,  and  has  a  focal  length  of  123  feet; 
another  was  made  for  Louis  XIV.  which  had  a  focal 
length  of  136  feet ;  and  Auzout  had  one  of  600  feet; 
which  preposterous  machine  he  was  unable  to  use  for  lack 
of  a  place  on  which  to  put  it. 

Sir  Isaac  Newton  despaired  of  ever  remedying  these 
evils  in  the  refracting  telescope,  and  devoted  his  labors  in 
this  field  to  the  construction  of  reflectors.  But  the  dis- 
covery that  the  dispersive  powers  of  different  kinds  of 
glass  were  not  proportional  to  their  refractive  powers  set 
opticians  to  work.  This  principle  may  be  illustrated  as 
follows  :  If  a  ray  of  sunlight  be  permitted  to  pass  through 
a  glass  prism,  it  will  be  separated  into  a  spectrum  of  a 
length  proportional  to  the  dispersive  power  of  the  glass, 
and  it  will  be  turned  out  of  a  straight  course  at  an  angle 


8 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 


proportional  to  its  refractive  power.  If  we  now  substi- 
tute for  this  prism  another  one  of  the  same  shape  but  of  a 
different  kind  of  glass,  the  spectrum  may  be  of  the  same 
length  but  be  thrown  to  a  greater  or  less  angular  distance 
than  by  the  first  prism.  Working  upon  this  principle, 
John  Dollond,  of  London,  immortalized  his  name  and 
founded  modern  telescopy  by  inventing  the  achromatic 
object  glass  in  1758.  This  consists  of  a  double  convex 
lenstof  crown  glass  combined,  as  in  Fig.  3, 
with  a  plano-convex  or  concavo-convex  lens 
of  flint  glass. 

The  proportion  of  the  refractive  and  dis- 
persive powers  of  these  two  kinds  of  glass 
is  such  that  the  flint  glass  neutralizes  the 
dispersion  caused  by  the  crown  glass  in  re- 
fracting the  rays  to  a  focus,  leaving  the 
latter  free  to  form  its  image  without  color. 
The  defect  is  not  absolutely  cured,  but 
becomes  of  little  moment  except  in  examin- 
ing an  object  of  extraordinary  brightness 
on  a  dark  background— e.g.,  Venus  against  a  dark  sky. 
The  spherical  aberration  is  also  corrected  by  the  figure 
given  to  the  compound  lens. 

The  tests  as  to  the  correction  of  chromatic  and  spheri- 
cal aberration  will  be  duly  given  when  we  come  to  con- 
sider the  examination  and  trial  of  object  glasses. 

As  the  achromatic  combination  has  superseded  the 
simple  double-convex  object  glass,  so  a  combination  of 
lenses  has  taken  the  place  of  the  single  eye-lens.  The 
image  formed  by  the  most  perfect  achromatic  objective 
would  appear  indistinct,  distorted  and  colored,  if  viewed 
through  a  common  double-convex  lens.  The  first  combi- 
nation lens,  or  eyepiece,  for  magnifying  the  image  was 


FIG.  3. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK. 


invented  by  Huygens  in  the  seventeenth  century,  and 
bears  his  illustrious  name.  It  consists  of  two  plano- 
convex lenses,  mounted  as  in  Fig.  4,  with  the  convex 
sides  of  both  turned  toward  the  image.  The  distance 
between  the  lenses  is  equal 
to  one-half  the  sum  of  their 
focal  lengths,  which  pro- 
duces an  achromatic  combi- 
nation. This  invaluable 
instrument  is  still  in  con- 
stant use,  except  in  cases 
where  micrometrical  meas- 
urements are  to  be  made.  It  is  known  as  the  negative 
eyepiece,  as  distinguished  from  the  one  presently  to  be 
described,  because  the  image  is  formed  between  the  lenses 
composing  it.  This  position  of  the  image  renders  it  im- 
possible to  use  the  Huygenian  eyepiece  in  cases  where 
it  is  required  that  transit  wires  or  a  micrometer  shall  be 
used  in  the  common  focus  of  the  objective  and  the  eye- 
piece. In  such  a  case  the 
yp  positive  eyepiece,  invented  by 
Ramsden  in  the  eighteenth 
^  century,  is  used.  This  is 
represented  in  Fig.  5.  The 
v  lenses  have  their  convex 
^  sides  turned  toward  each 
other,  and  the  image  is 
formed  just  beyond  the  lens 


FIG.  5. 


#,  which  is  known  in  all  eyepieces  as  the  field  glass,  while 
b  is  known  as  the  eye  glass.  The  common  focus  of  the 
object  glass  and  the  eyepiece  can  thus  receive  the  wires 
of  a  micrometer  or  transit  system. 

An   Huygenian,  or  negative,  eyepiece  is  equivalent  to 


10  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

a  single  lens  of  a  focal  length  equal  to  twice  the  product 
of  the  focal  lengths  of  the  component  lenses  divided  by 
their  sum.  A  positive  eyepiece  is  equivalent  to  a  single 
lens  of  a  focal  length  equal  to  the  product  of  the  focal 
lengths  of  the  component  lenses  divided  by  their  sum, 
minus  the  distance  between  them.  In  the  achromatic 
refractor,  the  magnifying  power  of  the  instrument  with  a 
given  eyepiece  is  expressed  by  the  ratio  of  their  focal 
lengths.  In  other  words,  the  power  of  a  given  eyepiece 
is  ascertained  by  dividing  the  focal  length  of  the  object 
glass  by  the  focal  length  of  the  eyepiece. 

It  is  highly  important  that  the  observer  know,  with  as 
great  accuracy  as  possible,  the  powers  of  each  of  the  eye- 
pieces of  his  telescope.  This  may  be  accomplished  in 
several  ways.  The  focus  of  a  single  lens  equivalent  to 
the  compound  one  in  question  may  be  calculated  by  one 
of  the  foregoing  rules,  and  the  focal  length  of  the  object 
glass  be  divided  by  that  of  the  equivalent  single  lens,  the 
quotient  giving  the  magnifying  power  of  that  eyepiece 
with  that  object  glass.  It  is  not  very  easy,  however,  to 
determine  the  focal  length  of  small  lenses.  A  better 
method  is  as  follows  :  Focus  the  telescope  accurately  on 
a  distant  object,  and  then  direct  the  tube  toward  the  sky. 
On  looking  at  the  eye-lens  of  the  eyepiece  it  will  be  seen 
that  the  image  of  the  object  glass  is  projected  thereupon 
as  a  small  luminous  disk.  Let  the  diameter  of  this  disk 
be  accurately  measured  ;  and  then  divide  the  diameter  of 
the  object  glass  by  that  of  the  luminous  circle,  and  the 
quotient  will  give  the  magnifying  power. 

The  measurement  of  this  tiny  circle  is  by  no  means 
easy,  especially  with  eyepieces  of  high  power.  It  may 
be  accurately  effected  with  a  Ramsden  dynamometer  or 
dynameter,  or  the  simple  and  precise  little  Berthon  dyna- 


THE    AMATEUR    TELESCOPJST's    HANDBOOK.  II 

mometer  made  by  Home,  Thornthwaite  &  Wood,  of  Lon- 
don, and  sold  for  ten  shillings.  The  measurement  may  be 
made  with  tolerable  accuracy  by  looking  at  the  disk  on 
the  eye  lens  with  a  small  magnifying  glass,  taking  its  diam- 
eter by  means  of  a  pair  of  compasses,  and  measuring  the 
distance  between  the  points  on  a  fine  and  accurate  scale. 

Modern  eyepieces,  however,  are  usually  marked  with 
their  equivalent  focal  length,  and  the  power  of  each  with 
a  given  object  glass  is  easily  ascertained. 

A  most  important  question  is  as  to  the  power  which 
may  be  used  upon  any  object  glass.  The  common  rule 
is  that  the  very  highest  power  which  a  good  telescope 
will  bear  under  the  most  favorable  atmospheric  condi- 
tions is  one  hundred  for  every  inch  of  aperture.  This  is 
doubtless  correct  ;  but  both  of  the  conditions  mentioned 
in  connection  with  it  must  be  present.  The  range  of 
powers  for  practical  work  under  ordinary  circumstances 
may  be  much  better  deduced  from  the  following  table, 
from  Chambers's  Astronomy,  p.  724  : 

APERTURES   OF 

6  in. 

35 
85 
160 
250 
360 
500 

Every  telescope,  however,  should  have  one  eyepiece 
of  the  highest  power  that  the  object  glass  will  bear,  for 
the  examination  of  close  double  stars,  etc.,  under  favor- 
able circumstances. 

As  regards  the  limit  of  vision  of  achromatic  telescopes, 


2  in. 

3  in. 

4  in. 

5  in. 

15 

20 

25 

30 

45 

55 

65 

85 

100 

no 

140 

170 

200 

300 

280 

420 

12  THE    AMATEUR   TELESCOPIST'S    HANDBOOK. 

Mr.  Chambers  gives  the  following  rule,  based  on  Arge- 
lander's  scale  of  magnitudes  : 

Multiply  the  logarithm  of  aperture  in  inches  by  5,  and 
add  9.2  to  the  result.  This  will  give  the  magnitude  of  the 
smallest  star  visible  with  that  aperture. 

For  instance,  to  find  the  magnitude,  according  to 
Argelander's  scale,  of  the  smallest  star  visible  in  a  tele- 
scope of  three  inches  aperture  : 

Log.  3,     .     .   0.477121 
5 

2.385605 
Add,    ...   9.2 

Mag.,    .     .       11.58 

By  this  rule  an  aperture  of  two  inches  may  be  expected 
to  show  a  star  of  magnitude  10.7  ;  one  of  four  inches,  12.2  ; 
one  of  five  inches,  12.6  ;  and  one  of  six  inches,  13.09, 
according  to  Argelander's  scale.  The  rule  is  based  on  the 
assumption  that  a  star  of  magnitude  9.2  is  the  smallest 
which  can  be  seen  by  the  average  observer  with  a  one- 
inch  telescope. 

Chambers  gives  a  modification  of  this  plan  by  Mr.  N. 
Pogson,  of  Madras,  which  is  more  accurate  for  the  indi- 
vidual observer  and  a  given  telescope  than  the  above. 
Determine  by  trial  the  smallest  star,  according  to  Arge- 
lander's or  Radcliffe's  scale,  which  you  can  see  with  an 
aperture  of  one  inch.  Then  the  limit  of  vision  with  any 
other  aperture  will  be  :  One-inch  limit  +  5  x  log.  aperture. 
Mr.  Pogson  observes  that  the  limit  of  vision  in  different 
observers  using  one  inch  of  aperture  will  differ  less  than 
people  imagine,  averaging  about  9^-. 

It  must  be  distinctly  understood  that  the  above  rules  only 
refer  to  isolated  stars,  or  those  in  a  field  containing  only 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  13 

stars  not  greatly  exceeding  the  test-star  in  magnitude. 
The  magnitude  of  the  companion  of  Rigel  (ft  Orionis), 
for  instance,  is  9,  and  so  it  should  be  visible  in  a  one-inch 
telescope  ;  but  the  glare  of  the  primary  star  will  com- 
pletely overwhelm  the  feeble  light  collected  from  the 
companion  by  the  object  glass,  and  the  little  star  will  be 
absolutely  invisible.  This  fact  must  be  carefully  borne 
in  mind  in  trying  double  stars. 

Argelander's  scale  of  magnitudes  has  been  referred  to 
in  connection  with  the  foregoing  rules  concerning  the 
limit  of  vision.  In  the  star-lists  given  in  this  book, 
Smyth's  scale  is  used.  Struve's  scale  is  perhaps  the 
most  generally  accepted.  The  following  table  will  show 
at  a  glance  the  corresponding  magnitudes  in  each  of  these 
scales  (G.  Knott)  : 

TABLE  OF  COMPARATIVE  MAGNITUDES. 
Smyth. 
6 

6-5 

7 

7.5 
8 

8-5 

9 

9-5 
10 
ii 

12 
13 

14 
15 

16 


W.  Struve. 

Argelander. 

5-7 

5-9 

6.3 

6.4 

6.5 

6.8 

6.9 

7-5 

7-4 

8 

7-9 

8.6 

8-3 

9 

8.9 

9-4 

9-3 

9-4 

10 

10 

10.4 

10.6 

10.7 

II.  2 

10.9 

n.8 

10.9 

12.4 

10.9 

13 

14  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

The  magnifying  of  celestial  objects  is  by  no  means  the 
sole  purpose  of  the  telescope  ;  the  collection  of  light  from 
them  is  an  equally  important  function  of  the  instrument, 
and,  in  the  case  of  the  nebulae  and  clusters,  the  more  im- 
portant function.  When  an  object  is  looked  at  with  the 
naked  eye,  the  retina  receives  only  so  many  rays  as  can 
fall  upon  the  pupil  of  the  eye  ;  but  by  the  use  of  the  tele- 
scope as  many  rays  can  be  brought  to  the  retina  as  fall 
upon  the  entire  object  glass.  "  The  pupil  of  the  human 
eye  in  its  normal  state  has  a  diameter  of  about  one-fifth  of 
an  inch,  and  by  the  use  of  the  telescope  it  is  virtually  in- 
creased in  surface  in  the  ratio  of  the  square  of  the  diam- 
eter of  the  objective  to  the  square  of  one-fifth  of  an  inch."  * 
Thus,  to  ascertain  the  light-collecting  power  of  an  objec- 
tive, we  divide  the  square  of  the  diameter  of  the  object 
glass  by  the  square  of  ^  ;  or,  what  is  the  same  thing,  we 
multiply  the  square  of  the  diameter  by  25  ;  and  the 
quotient  or  product,  as  the  case  may  be,  will  give  the 
light-collecting  power  of  the  object  glass  as  compared 
with  that  of  the  naked  eye. 

By  the  defining  power  of  an  objective  is  meant 
its  capacity  for  separating  closely  adjacent  points  of 
visible  matter.  By  its  illuminating  power  is  meant  its 
capacity  for  exhibiting  very  faintly  lighted  objects. 
The  defining  and  illuminating  power  of  a  given  object 
glass  of  any  given  aperture  depends  upon  its  focal 
length.  Should  the  focal  length  be  very  short,  its 
definition  will  be  inferior  but  its  illumination  good,  a 
fact  which  is  utilized  in  the  comet-seeker.  Should  the 
focal  length,  on  the  contrary,  be  excessive,  the  defini- 
tion will  be  good,  but  the  illumination  poor.  Moreover, 

*  Newcomb  and  Holden,  Astronomy,  p.  56. 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  15 

the  greater  the  focal  length,  the  smaller  is  the  field 
of  view,  and  vice  versa.  A  focal  length  which  furnishes 
for  any  given  glass  the  maximum  of  both  defining  and 
illuminating  power  is  fourteen  or  fifteen  inches  for  every 
inch  of  aperture. 


CHAPTER   II. 

TESTING    THE    OBJECT    GLASS. — EYEPIECES. TUBES. 

THE  figuring  of  a  telescopic  objective  is  one  of  the 
most  difficult  and  delicate  operations  in  the  arts,  espe- 
cially when  its  diameter  exceeds  five  or  six  inches.  *  This 
being  the  case,  it  is  to  be  expected  that  the  making  of 
the  highest  grade  of  object  glasses  should  remain,  as  it 
does,  in  the  hands  of  a  few  artists  of  the  highest  intelli- 
gence and  skill.  The  manufacture  of  perfectly  homo- 
geneous glass  for  this  purpose  is  also  a  difficult  operation. 
The  result  of  these  facts  is  that  object  glasses  of  the  first 
class  must  necessarily  be  expensive  instruments.  An 
estimate  (although  so  rough  as  to  be  of  little  use)  of  the 
cost  of  a  high-grade  objective  may  be  formed  by  a  rule 
given  by  Professor  Newcomb  :  multiply  the  cube  of  the 
aperture  in  inches  by  $T  and  also  by  $1,75  ;  the  products 
will  give  the  minimum  and  maximum  respectively  of  the 
probable  price.  A  first-class  three-inch  glass,  according 
to  this  rule,  would  cost  from  $27  to  $47.25  ;  a  four-inch 
from  $64  to  $112,  and  so  on.  I  will  give,  however,  in 
another  place,  the  actual  prices  of  object  glasses  as  sup- 
plied by  some  of  the  best  opticians  of  England  and  the 
United  States. 

In  testing  an  objective  it  should  be  first  carefully  ex- 
amined in  its  cell.  It  should  appear  brightly  polished 

*  On  this  subject  see  a  most  interesting  article  by  Professor  New- 
comb,  "  The  Story  of  a  Telescope,"  in  Scribner's  Monthly  for  1873, 
vol.  vii.  p.  44. 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  17 

and  free  from  scratches,  and  preferably  without  bubbles  or 
sand-holes.  These  things,  it  is  truly  said,  only  cause  the 
loss  of  a  little  light,  and  are  not  incompatible  with  satis- 
factory definition  ;  but  the  possessor  of  a  small  telescope 
can  ill  afford  to  lose  any  light.  Still,  these  faults  are  not 
sufficient  by  themselves  to  warrant  the  rejection  of  an 
object  glass.  But  stria,  or  waves,  and  unequal  density  of 
different  parts  of  the  glass  are  most  serious  defects. 

The  telescope  being  fully  mounted  and  ready  for  use, 
the  object  glass  should  be  given  the  following  tests  : 

1.  As  to  whether  the  chromatic  aberration  has  been 
corrected. 

Point  the  telescope  toward  Jupiter  or  the  moon, 
using  in  the  latter  case  the  lowest  power,  and  focus 
carefully.  Now,  if  on  pushing  in  the  eyepiece  a  purple 
ring  appears  around  the  edges  of  the  disk,  and  on  draw- 
ing it  out,  a  green  one,  then  the  chromatic  aberration  has 
been  corrected,  since  these  are  the  central  colors  of  the 
secondary  spectrum,  appearing  where  they  should. 

2.  As  to  whether    the  spherical  aberration   has  been 
corrected. 

Point  the  telescope  toward  a  star  of  moderate  brilliancy, 
say  of  the  third  magnitude,  and  focus  carefully.  Cover 
the  object  glass  with  a  piece  of  cardboard  in  which  has 
been  cut  a  circular  aperture  of  a  diameter  equal  to  one-half 
that  of  the  object  glass,  in  such  a  manner  that  the  glass 
and  the  opening  in  the  cardboard  shall  be  concentric.  If 
on  now  looking  through  the  telescope  we  find  the  star 
still  in  focus,  the  spherical  aberration  has  been  duly  cor- 
rected. If,  however,  the  eyepiece  has  to  be  pushed  fur- 
ther in  to  obtain  a  true  focus,  then  the  spherical  aberra- 
tion has  been  over-corrected  ;  while  if  it  has  to  be  drawn 
further  out,  this  aberration  has  been  under-corrected. 


l8  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

The  following  valuable  remarks  are  from  the  Rev.  T.  W. 
Webb  :  * 

"  The  image  should  be  neat  and  well  defined  with  the 
highest  power,  and  should  come  in  and  out  of  focus 
sharply  ;  that  is,  become  indistinct  by  a  very  slight  motion 
on  either  side  of  it.  A  proper  test-object  must  be  chosen ; 
the  moon  is  too  easy  ;  Venus  too  severe,  except  for  first- 
rate  glasses  ;  large  stars  have  too  much  glare  ;  Jupiter  or 
Saturn  are  far  better  ;  a  close  double  star  is  best  of  all 
for  an  experienced  eye  ;  but  for  general  purposes  a 
moderate-sized  star  will  suffice  ;  its  image,  in  focus,  with 
the  highest  power,  should  be  a  very  small  disk,  almost  a 
point,  accurately  round,  without  *  wings '  or  rays  or  misti- 
ness or  false  images,  or  appendages,  except  one  or  two 
narrow  rings  of  light,  regularly  circular,  and  concentric 
with  the  image  ;  and  in  a  regularly  dark  field  ;  a  slight 
displacement  of  the  focus  either  way  should  enlarge  the 
disk  into  a  luminous  circle.  If  this  circle  is  irregular  in 
outline,  or  much  brighter  or  fainter  toward  the  centre, 
or  much  better  defined  on  one  side  of  the  focus  than 
the  other,  the  telescope  may  be  serviceable,  but  is  not  of 
high  excellence.  The  chances  are  many,  however,  against 
any  given  night  being  fine  enough  for  such  a  purpose, 
and  a  fair  judgment  may  be  made  by  day  from  the  figures 
on  a  watch-face,  or  a  minute  white  circle  on  a  black 
ground,  or  the  image  of  the  sun  on  a  thermometer  bulb 
placed  as  far  off  as  possible.  An  achromatic,  notwith- 
standing the  derivation  of  its  name,  will  show  color 
under  high  powers  where  there  is  much  contrast  of  light 
and  darkness.  This  '  outstanding  '  or  uncorrected  color 
results  from  the  want  of  a  perfect  balance  between  the 
optical  properties  of  the  two  kinds  of  glass  of  which  the 

*  Celestial  Objects  for  Common  Telescopes,  p.  3. 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  19 

object  glass  is  constructed  ;  it  cannot  be  entirely  remedied, 
but  it  ought  not  to  be  obtrusive.  In  the  best  instruments 
it  forms  a  fringe  of  violet  or  blue  round  luminous  objects 
in  focus  under  high  powers,  especially  Venus  in  a  dark 
sky.  A  red  or  yellow  border  would  be  bad  ;  but  before 
condemning  an  instrument  from  such  a  cause,  several  eye- 
pieces should  be  tried,  as  the  fault  might  be  there,  and 
be  easily  and  cheaply  remedied." 

The  "  wings  "  spoken  of  in  the  above  extract  may  be 
due  to  several  causes.  They  may  arise  from  the  object- 
glass  lenses  having  been  screwed  too  tightly  together,  and 
the  fault  may  be  corrected  by  very  slightly  loosening  the 
screw-cell  in  which  they  are  placed.  This  cause,  how- 
ever, is  an  uncommon  one.  A  much  more  usual  cause 
lies  in  the  objective's  not  being  in  every  part  of  uniform 
refractive  power — a  very  bad  and  virtually  incurable 
defect.  The  defective  portion  may  indeed  be  covered  up 
with  an  opaque  screen,  and  thus,  perhaps,  fair  definition 
be  secured  at  the  expense  of  light ;  but  the  better  course 
is  to  reject  peremptorily  any  glass  which  has  not  in  every 
part  the  same  refractive  power. 

These  "  wings  "  may  also  be  due  to  the  fact  that  the 
object  glass  is  not  set  at  right  angles  with  the  optical 
axis  of  the  telescope  ;  a  fault  which  would  be  quite 
unpardonable  in  the  work  of  an  optician,  and  which 
could  easily  be  avoided  by  proper  care  in  that  of  an 
amateur.  They  may  also  be  caused  by  a  slight  inclina- 
tion of  the  eyepiece.  This  may  be  detected  by  covering 
each  of  the  glasses  of  the  eyepiece  with  a  circular  card- 
board screen  pierced  in  the  centre  with  a  small  aperture, 
and  covering  the  object  glass  with  a  similar  pierced 
screen.  If  the  eyepiece  is  correctly  centred,  it  will  be 
possible  to  see  through  the  three  openings  at  once. 


20  THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

If  the  tube  of  the  telescope  is  not  somewhat  greater 
in  diameter  than  the  object  glass,  a  particular  form  of 
"  wing  "  may  be  seen  extending  upward  from  a  star  like 
the  tail  of  a  little  comet,  when  the  instrument  is  used  in 
the  open  air.  This  is  most  apt  to  be  the  case  when  the 
tube  is  of  wood,  and  the  amateur  who  makes  his  own  tele- 
scope needs  to  be  warned  of  the  danger.  The  cause  of 
this  annoying  defect,  which  once  nearly  caused  the  rejec- 
tion by  Alvan  Clark  of  one  of  his  own  earlier  object- 
glasses  as  worthless,*  is  that  a  wooden  tube  under  the 
cold  sky  radiates  heat  from  its  upper  surface  and  at  the 
same  time  receives  warmth  from  the  earth  under  it.  The 
result  is  that  a  thin  layer  of  warm  air  lies  at  the  bottom  of 
the  tube,  and  an  equally  thin  layer  of  colder  air  exists  at 
the  upper  surface.  This  causes  a  slight  upward  refrac- 
tion of  the  rays  which  pass  through  the  outer  edges  of  the 
object  glass,  and  thus  produces  the  comet-like  tail.  The 
remedy  or  preventive  is  to  make  the  tube  of  sufficient 
diameter  to  bring  the  layers  of  warm  and  cool  air  out  of 
the  path  of  the  rays,  or  to  cover  the  tube  with  tinfoil, 
which,  by  its  inferior  radiating  power,  will  prevent  the 
trouble  in  question. 

According  to  Dawes  f  (one  of  the  highest  of  authorities 
on  the  telescope),  the  severest  test  of  figure  for  an  achro- 
matic objective  is  the  similarity  of  the  image  of  a  bright 
star,  viewed  with  the  focus  too  long,  to  the  same  image 
viewed  when  the  focus  is  to  an  equal  linear  extent  too 
short ;  the  amount  of  the  dissimilarity  being  a  measure 
of  the  imperfection  of  the  instrument. 

The  examination  of  stars  out  of  focus  is  an  important 

*  See  Professor  Newcomb's  article,  before  referred  to. 
f  Chambers,  p.  617. 


THE    AMATEUR    TELESCOPISTS    HANDBOOK. 


21 


aid  in  the  testing  of  an  object  glass  and  of  its  mounting. 
I  append  a  series  of  figures  (from  Professor  Newcomb) 
giving  the  appearance  of  spectral  images  of  stars  in  dif- 
ferent telescopes,  with  the  focus  imperfect  through  the 
pushing  in  of  the  eyepiece,  and  of  the  same  images  with 
the  focus  imperfect  through  the  drawing  out  of  the 
same. 

There  is,  to  a  practised  eye,  no  better  test  of  the  charac- 
ter of  an  object  glass  than  the  image  formed  by  it  of  a 
star  of  the  third  or  fourth  magnitude.  A  bright  little  disk 
surrounded  by  from  one  to  three  delicate  thread-like  con- 
centric rings  (called,  technically,  diffraction  rings)  proves 
pretty  conclusively  the  general  excellence  of  the  object 


II 


ffl 


IV        V 


FIG.  6, 


I.  Images  as  they  should  be. 
II.  Spherical  aberation  shown  by  the  light  and  dark  centres. 

III.  Objective  not  spherical  but  elliptical. 

IV.  Glass  not  uniform — a  very  bad  and  incurable  case. 
V.  One  side  of  objective  nearer  than  other.     Adjust  it. 


22  THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

glass.  I  give  below  two  figures  by  Captain  Noble,  the 
first  showing  what  a  star-image  ought  to  be,  and  the  sec- 
ond showing,  with  an  almost  comic  truthfulness,  what  it 
sometimes  is,  but  most  emphatically  ought  not  to  be.* 
The  sharpness  of  this  image  should  be,  in  a  good  tele- 
scope, seriously  deranged  by 
a  movement  of  the  eye  piece 
to  the  extent  of  one-tenth 
of  an  inch  either  way.  If 
this  movement  makes  but 
little  change,  the  object 
glass  is  not  all  it  ought  to 

FIG.  7.        FIG.  8. 

It  will  be  well  for  the  tyro 

to  get  an  experienced  telescopist  to  make  the  foregoing 
tests  for  him,  if  the  services  of  such  a  one  can  be  com- 
manded. The  following  remarks  J  by  Sir  Howard  Grubb, 
of  the  great  Dublin  firm  of  telescope-makers,  are  full  of 
truth  and  humor,  and  are  commended  to  the  reader's  care- 
ful attention.  Especially  are  the  observations  as  to  the 
necessity  of  a  certain  education  of  the  eye  for  telescopic 
work  to  be  diligently  noted  : 

"  It  is  almost  impossible  to  give  any  directions  which 
will  enable  a  tyro  to  detect  whether  his  telescope  is  good 
or  not.  It  would  be  about  as  hopeless  a  task  as  to  try  to 
convey  to  a  person  wholly  uneducated  in  art,  and  who 
had  never  seen  anything  but  daubs,  how  to  know  a  well- 
painted  picture.  One  great  mistake  which  beginners  fall 

*  The  diffraction  rings  in  these  figures  are  necessarily  represented 
as  much  thicker  than  they  are  in  reality, 
f  Chambers,  p.  617. 
JSee  Oliver's  Astronomy  for  Amateurs,  p.  29. 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  23 

into,  and  which,  it  is  to  be  feared,  most  text-books  rather 
encourage,  is  that  of  supposing  that,  because  a  telescope 
of  a  certain  size  should  divide  such  a  star,  the  telescope  is 
necessarily  bad  because,  when  he  puts  his  eye  to  it,  he 
does  not  see  it  so  divided.  l  The  most  important  part  of 
the  telescope  is  the  man  at  the  small  end,'  said  a  cele- 
brated astronomer.  There  is  such  a  thing  as  education 
of  the  eye,  and  even  though  a  person  have  good,  sharp, 
ordinary  eyesight,  it  by  no  means  follows  that  he  will  see 
nearly  as  much  with  a  telescope  at  first  as  a  person  of  very 
ordinary  sight  who  has  educated  his  eye  by  experience. 

"  Text -books  on  the  subject,  by  giving  lists  of  objects 
which  are  capable  of  being  divided  by  different  sized  tele- 
scopes, and  pictures  (?)  of  planets,  etc.,  as  they  should  be 
seen,  rather  encourage  the  mistake. 

"  An  enthusiastic  amateur  receives  a  telescope  he  has 
been  waiting  for  for  months  ;  meanwhile  he  has  studied 
up  the  text-book  on  the  subject,  and  he  finds  that  a  tele- 
scope of  the  size  of  his  should  have  a  power  of  x,  and 
divide  such  and  such  stars.  The  moment  he  gets  his 
instrument  into  position  he  puts  on  his  highest  eye  piece 
and  points  to  these  objects,  and  great  is  his  disgust  to  see 
something  like  a  ball  of  cotton  wool  on  a  flaming  gas-lamp. 
He  is  not  told  that  this  object  can  be  so  seen  under  favor- 
able circumstances  and  with  educated  eyes,  or  that  the 
beautiful  pictures  he  sees  of  Saturn  and  Jupiter  are  either 
the  result  of  a  number  of  observations,  or  what  was  seen 
on  some  exceptional  occasion,  and  he  condemns  at  once 
what  in  experienced  hands  may  prove  an  excellent  instru- 
ment. An  experienced  observer  judges  of  a  telescope  not 
so  much  by  trying  what  stars  it  will  divide,  as  by  the 
appearance  of  any  particular  stars  which  he  is  familiar 
with." 


24  THE    AMATEUR    TELESCOPIST  S   HANDBOOK. 

The  observer  may  test  his  telescope  for  definition  and 
illumination  by  the  following  objects,  suggested  by  Mr. 
Lockyer : 

A  2-inch  telescope  with  powers  of  from  60  to  100 
should  exhibit  : 

Polaris,  y  Arietis,  a  Geminorum, 

a  Piscium,  p  Herculis,  y  Leonis, 

.u  Draconis,          £   Urs.  Majoris,       £   Cassiopeae. 

A  4-inch  with  powers  of  from  80  to  100  should  exhibit: 

/3  Orionis,  a  Lyrse,  6  Geminorum, 

£  Hydrse,  s  Leonis,  a  Cassiopeae, 

s  Bootis,  y  Ceti,  e  Draconis. 

Different  eyes  and  telescopes,  however,  will  give  very 
different  results  upon  the  above  stars,  y  Leonis,  for 
example,  would  be  a  very  severe  test  for  a  2-inch  ;  while 
ft  Orionis  and  e  Bootis  have  often  been  seen  with  a  j-inch 
and  with  even  smaller  apertures. 

Concerning  eyepieces  there  is  little  to  be  said.  The 
construction  of  them,  while  by  no  means  so  easy  as  to 
greatly  tempt  the  amateur  to  make  them  for  himself, 
since  very  accurate  adjustments  are  required  in  them,  is 
still  within  the  power  of  an  ordinarily  skilful  optician,  and 
they  are  consequently  easy  to  obtain  and  comparatively 
inexpensive,  their  prices  ordinarily  ranging  from  $4.50  to 
$8.00.  The  Huygenian  form,  or  one  of  its  modern  modi- 
fications, will  of  course  be  employed,  unless  the  observer 
desires  to  make  use  of  a  micrometer,  which,  it  must  be 
understood,  is  practically  out  of  the  question  for  any  tele- 
scope unprovided  with  a  driving-clock. 

The  materials  used  for  telescope  tubes  are  wood,  brass, 
steel,  or  a  species  of  papier-macht  for  instruments  up  to 


THE    AMATEUR    TELESCOPIST'S   HANDBOOK.  25 

three  or  four  inches  of  aperture  ;  wood  or  brass  for  the  next 
series,  and  frequently  sheet-iron  or  steel  for  the  largest 
sizes.  Our  observer's  telescope  will  probably  have  a  tube 
of  brass— possibly  steel — if  purchased  in  a  complete  form. 
Should  he  construct  his  own  telescope,  the  question  as  to 
the  material  of  the  tube  will  be  an  important  one.  Wood 
is  apt  to  split ;  brass  is  very  expensive.  A  tube  made  by 
pasting  alternate  layers  of  card  and  calico  over  a  wooden 
mould,  which  is  then  withdrawn,  is  said  by  Mr.  Proctor  to 
be  both  light  and  strong.  This  form  of  tube  is  excel- 
lently adapted  for  telescopes  up  to  two  and  one-half 
inches  of  aperture,  but  for  anything  larger  another  plan 
suggested  to  Proctor  by  Mr.  Sharp,  of  St.  John's  College, 
Cambridge,  is  greatly  to  be  preferred.  This  is  to  have 
the  tube  made  of  tin.  covered  with  layers  of  brown  paper, 
well  pasted  and  thicker  towards  the  middle  of  the  tube. 
This,  according  to  Mr.  Sharp,  forms  a  light  and  strong 
telescope  tube,  almost  wholly  free  from  vibration.  I 
strongly  recommend  this  plan  as  cheap  and  effective. 

The  inside  of  the  tube  must  be  colored  dead  black  to 
prevent  the  reflection  of  any  light  from  it.  The  follow- 
ing is  the  best  composition  for  this  purpose  :  Lampblack, 
five  parts  ;  finely  pulverized  gum-arabic,  two  parts ;  brown 
sugar,  one  part.  Mix  to  a  thick  paste  with  water,  and 
apply  with  a  piece  of  flannel.  Two  coats  may  be  neces- 
sary. The  proportions  should  be  carefully  preserved, 
since  if  there  is  too  much  lampblack  the  composition  will 
rub  off,  while  if  there  is  too  little  it  will  reflect  light. 

The  above  mixture  adheres  readily  to  wood  or  paper, 
but  not  very  well  to  metal.  A  tin  tube  may  be  lined  with 
brown  paper  previously  blackened  with  the  compound. 
Brass  may  be  blackened  by  means  of  a  solution  of  one 
drachm  platinum  bichloride  and  one  grain  nitrate  of  silver 


26  THE   AMATEUR   TELESCOPIST*S   HANDBOOK. 

in  one  and  one-half  ounces  of  water.  The  brass  is  first 
thoroughly  cleaned  and  then  warmed,  and  the  solution  is 
applied  with  a  tuft  of  cotton.  Rub  till  dry,  and  finish  off 
with  a  little  powdered  graphite,  taking  care  not  to  rub 
this  latter  so  as  to  produce  a  polish.  (M.  Carey  Lea.) 
A  much  cheaper  and  equally  effective  way  of  blackening 
brass  is  to  clean  it  thoroughly  and  immerse  it  for  ten 
minutes  in  a  ten  per  cent,  solution  of  potassium  sulphide. 
The  metal  is  then  washed  in  water  and  dried,  and  will  be 
found  to  be  thoroughly  and  permanently  blackened. 

It  is  necessary,  for  reasons  mentioned  on  page  20,  to 
have  the  tube  somewhat  larger  than  is  required  for  the 
admission  of  the  object-glass.  "  Stops  "  or  diaphragms 
pierced  with  apertures  to  transmit  all  the  rays  except 
those  falling  through  the  extreme  edges  of  the  objective, 
are  usually  placed  in  the  tube,  and  serve  to  cut  off  the 
"  ragged  edge  "  of  the  field  of  view,  and  as  an  additional 
protection  against  light  reflected  from  the  interior  of  the 
tube.  I  have  never  found  these  stops  necessary  if  the 
inside  of  the  telescope  is  thoroughly  blackened.  The 
amateur  who  has  a  telescope  made  under  his  own  super- 
vision, or  who  makes  it  himself,  must  be  particularly  care- 
ful that  the  ends  of  the  tube  are  cut  squarely  at  right 
angles  with  its  length,  to  insure  the  proper  centring  of 
all  the  lenses  ;  in  fact,  the  ends  had  better  be  "  trued  "  in 
a  lathe. 

The  eyepieces  slip  into  a  tube  at  the  eye  end  of  the 
telescope,  which  is  capable  of  motion  back  and  forth  for 
the  adjustment  of  the  focus.  This  movement  is  usually, 
and  should  be  always,  effected  by  means  of  rack-work. 
The  focusing  apparatus  should  work  smoothly  and 
closely  and  with  as  little  "back-lash"  as  possible  ;  />., 
when  the  movement  of  the  button  is  reversed,  the  reverse 


THE    AMATEUR    TELESCOPIST*S    HANDBOOK.  27 

motion  of  the  eyepiece  should  begin  at  once,  without  any 
intermediate  play  of  the  rack-work. 

The  construction  of  a  telescope,  aside  from  its  optical 
parts,  is  fairly  within  the  powers  of  an  ordinarily  skil- 
ful amateur  handicraftsman.  But  the  student  may  prefer 
to  purchase  his  telescope  complete,  and  it  cannot  be 
doubted  that  when  this  is  possible,  it  is  by  far  the  best 
course  for  him  to  pursue. 


CHAPTER  III. 


THE    STAND. 

SCARCELY  less  important  than  a  good  telescope  is  a  good 
stand.  There  is  not  a  doubt  that  a  telescope  set  upon  a 
firm  and  steady  mounting  will  not  only  give  more  pleas- 
ure in  its  use,  but  will  exhibit  more  difficult  objects  than 
a  larger  and  perhaps  finer  instrument  set  upon  a  rickety, 
unsteady  and  clumsy  stand.  Such  a  mounting  as  the 
latter  will  be  a  source  of  endless  vexation  and  trouble  ;  so 
let  the  possessor  of  a  telescope  see  to  it  that  his  stand  is 
as  firm  as  the  nature  of  things  admits. 

Small  telescopes  are  sometimes  mounted  on  what  is 
known  as  the  pillar-and-claw  stand  :  an 
upright  pillar  supported  upon  three  feet. 
A  more  usual  and  much  more  convenient 
mounting  is  a  wooden  closing  tripod. 
Telescopes  mounted  upon  such  stands 
are  usually  provided  with  two  motions  : 
one  in  altitude,  or  from  the  horizon  to 
the  zenith,  and  the  other  in  azimuth,  or 
at  right  angles  to  the  first.  This  is  known 
as  the  altazimuth  stand.  Several  devices 
have  been  contrived  to  render  this  system 
of  mounting  convenient  and  reliable, 
among  which  there  is  nothing  better  than 
the  plan  described  by  R.  A.  Proctor,*  and  represented  in 
Fig.  9. 


FIG.  9. 


*  Half-hours,  p.  16. 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  29 

'*  The  slow  movement  in  altitude,"  says  Mr.  Proctor, 
"  is  given  by  rotating  the  rod  h  e,  the  endless  screw  in 
which  turns  the  small  wheel  at  by  whose  axle  in  turn  bears 
a  pinion-wheel  working  in  the  teeth  of  the  quadrant  a. 
The  slow  movement  in  azimuth  is  given  in  like  manner 
by  rotating  the  rod  h'  e ,  the  lantern-wheel  at  the  end 
of  which  turns  a  crown-wheel  on  whose  axle  is  a  pin- 
ion-wheel working  on  the  teeth  of  the  circle  c.  The 
casings  at  e  and  e',  in  which  the  rods  h  e  and  h'  e'  re- 
spectively work,  are  so  fastened  by  elastic  cords  that  an 
upward  pressure  on  the  handle  h,  or  a  downward  press- 
ure on  the  handle  ti,  at  once  releases  the  endless  screw 
or  the  crown-wheel  respectively,  so  that  the  telescope  can 
be  swept  at  once  through  any  desired  angle  in  altitude  or 
azimuth.  This  method  of  mounting  has  other  advan- 
tages :  the  handles  are  conveniently  situated  and  constant 
in  position  ;  also,  as  they  do  not  work  directly  on  the  tel- 
escope, they  can  be  turned  without  setting  the  tube  in 
vibration."  But  Mr.  Proctor  continues  :  "  I  do  not  rec- 
ommend the  mounting  to  be  exactly  as  shown  in  the 
figure.  That  method  is  much  too  expensive  for  an  alt- 
azimuth. But  a  simple  arrangement  of  belted  wheels  in 
place  of  the  toothed  wheels  a  and  c  might  very  readily  be 
prepared  by  the  ingenious  amateur  telescopist ;  and  I  feel 
certain  that  the  comfort  and  convenience  of  the  arrange- 
ment would  amply  repay  him  for  the  labor  it  would  cost 
him.  My  own  telescope — though  the  large  toothed  wheel 
and  the  quadrant  were  made  inconveniently  heavy 
(through  a  mistake  of  the  workman  who  constructed  the 
instrument) — worked  as  easily  and  almost  as  convenient- 
ly as  an  equatorial." 

The  observer  with  an  altazimuth  is  compelled  to  search 
for  every  object  which  is  not  visible  to  the  naked  eye,  by 


30  THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

the  aid  of  directions  as  to  the  situation  of  the  object 
with  reference  to  visible  stars.  Great  pains  have  been 
taken  in  the  lists  of  celestial  objects  given  in  this  book, 
to  make  these  directions  full  and  accurate  ;  but  it  must 
be  admitted  that  in  many  cases  patience  and  time  are 
required  to  "  pick  up  "  the  object.  Still,  this  is  the  only 
course  open  to  the  telescopist  whose  only  means  of  ob- 
servation is  an  altazimuth,  or  even  an  equatorial  without 
graduated  circles  ;  and  this  is  the  class  of  observers  for 
which  this  book  is  principally  prepared.  But  should  the 
amateur  be  fortunate  enough  to  be  able  to  provide  him- 
self with  an  equatorial  mounting  with  graduated  circles, 
he  is  at  once  placed  beyond  the  necessity  of  "  fishing  "  for 
objects,  to  use  Admiral  Smyth's  expressive  phrase,  since 
he  can  at  once  direct  his  telescope  to  the  desired  place. 

As  the  equatorial  mounting  is  incomparably  superior  to 
all  others,  and  is  the  one  almost  invariably  employed  by 
professional  astronomers  for  extra-meridional  telescopic 
work,  every  student  of  the  telescope  should  be  acquainted 
with  its  principles  and  the  method  of  using  it.  It  consists 
essentially  of  an  axis  placed  parallel  with  the  axis  of  the 
earth,  with  another  axis  set  at  right  angles  to  it.  The 
first  of  these  is  called  the  polar  axis,  the  second  the 
declination  axis.  At  one  end  of  the  declination  axis,  and 
at  right  angles  to  it,  is  fixed  the  telescope,  and  at  the 
other  a  weight  to  counterpoise  the  telescope.  As  all 
celestial  objects  appear  to  move  in  circles  about  the  pole 
of  the  heavens,  it  is  evident  that  if  the  polar  axis  of  a 
telescope  mounted  as  above  be  caused  to  rotate  in  a 
direction  the  same  as  that  of  the  apparent  motion  of  the 
stars,  and  at  the  same  rate,  it  will  continue  to  point  to 
any  star  to  which  it  may  be  directed,  as  it  describes  its 
course  in  the  sky.  If  a  telescope  mounted  on  an  altazi- 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  31 

muth  stand  be  tilted  so  that  its  previously  upright  stand- 
ard points  to  the  pole  of  the  heavens,  or,  in  other  words, 
is  parallel  with  the  earth's  axis,  it  is  plain  that  by  pointing 
the  instrument  at  any  given  star,  and  rotating  the  standard 
in  a  direction  contrary  to  that  of  the  earth's  diurnal 
motion,  and  at  a  corresponding  rate,  the  telescope  will 
follow  the  star.  This  would  be  an  equatorial  in  its  sim- 
plest form. 

The  place  of  a  star  or  other  object  is  located  upon  the 
celestial  sphere  in  the  following  manner  :  First,  by  its 
distance,  reckoned  on  the  celestial  equator,  from  the 
vernal  equinox,  or  as  it  is  frequently  called,  the  First 
Point  of  Aries.  This  is  called  its  Right  Ascension,  and  is 
usually  expressed  in  hours,  minutes,  and  seconds,  but 
sometimes  in  degrees,  minutes,  and  seconds  ;  the  equator 
being  divided  into  twenty-four  hours  or  three  hundred 
and  sixty  degrees.  Second,  by  its  angular  distance  north 
or  south  from  the  equator,  measured  on  the  great  circles 
passing  through  the  poles.  This  is  called  its  Declination, 
and  is  invariably  expressed  in  degrees,  minutes,  and 
either  seconds,  or,  more  frequently,  decimals  of  minutes. 
Sometimes  the  second  co-ordinate  is  stated  in  North 
Polar  Distance — a  phrase  which  explains  itself. 

Now,  if  the  polar  axis  of  an  equatorial  be  rotated,  the 
end  of  the  telescope  will  describe  circles  parallel  with  the 
equator ;  and  if  the  declination  axis  be  rotated,  the  end 
of  the  telescope  will  describe  great  circles  passing  through 
the  poles.  It  is  evident,  then,  that  if  properly  graduated 
circles  be  attached  to  these  two  axes,  the  right  ascension 
and  declination  of  any  object  to  which  the  telescope  is 
pointed  may  be  easily  ascertained ;  and,  conversely,  if  the 
right  ascension  and  declination  of  any  object  are  known, 
the  instrument  may  be  readily  directed  to  it. 


32  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

Fig.  10  represents  a  portable  equatorial  stand.  It  will 
be  noted  that  an  arrangement  is  provided  for  setting  the 
polar  axis  parallel  with  the  axis  of  the  earth,  according 
to  the  latitude  of  the  place  in  which  the  instrument  is 


FIG.  10. 

used.  In  large  fixed  stands  for  observatory  use,  the 
position  of  the  polar  axis  is  permanently  fixed  by  the 
maker.  Verniers  are  provided  for  setting  and  reading 
the  circles,  and  sometimes  small  microscopes  for  more 
conveniently  examining  them. 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  33 

In  using  the  equatorial,  the  stand  must  be  placed  in 
such  a  manner  that  the  polar  axis  is  parallel  with  the  axis 
of  the  earth  ;  that  the  declination  circle  shall  read  o° 
when  the  telescope  points  to  the  celestial  equator  ;  that 
the  polar  axis  shall  be  in  the  meridian  ;  and  that  the  index 
of  the  right  ascension  or  hour-circle  shall  read  o°  when 
the  telescope  is  placed  in  the  meridian.  In  scientific 
observation  these  adjustments  must  be  made  with  great 
accuracy,  and  the  reader  is  referred  to  any  work  on  prac- 
tical astronomy  for  the  methods  employed.  A  portable 
equatorial,  however — unless  the  student  is  fortunate 
enough  to  possess  a  fixed  observatory — will  have  to  be 
adjusted  for  each  evening's  observation,  and  minute  ac- 
curacy is  hardly  practicable,  but  the  observer  can  with 
but  little  trouble  arrange  his  stand  with  sufficient  cor- 
rectness for  an  amateur's  purposes.  This  is  accomplished 
as  follows  : 

Set  the  instrument  approximately  in  the  meridian  by 
means  of  a  compass  or  by  reference  to  the  pole-star. 
Fix  the  tripod  firmly,  so  that  the  base  of  the  equatorial 
shall  be  level.  The  following  adjustments  must  then  be 
made  :  * 

i.    To  set  the  polar  axis  parallel  with  the  earth's  axis. 

Some  portable  equatorials  possess  a  graduated  scale  by 
which  the  adjustment  may  be  made  with  tolerable  accu- 
racy if  the  base  of  the  stand  be  perfectly  levelled.  If  this 
be  wanting,  the  adjustment  is  effected  as  follows  :  Choose 
some  star  whose  position  is  known  and  which  is  at  once 
near  the  meridian  and  near  the  zenith.  Point  the  tele- 
scope to  it  and  read  the  declination  circle  ;  then  turn  the 
polar  axis  half  round,  the  telescope  still  bearing  on  the 

*  Chambers'  Astronomy,  pp.  653-657. 


34  THE    AMATEUR    TELESCOPIST  S   HANDBOOK. 

star,  and  again  read  the  circle.  Add  the  two  readings 
and  divide  by  2,  which  will  give  the  mean  observed 
declination.  If  the  star  is  not  near  the  zenith,  correct 
this  mean  declination  for  refraction.  Compare  the  ob- 
served declination  with  the  true  declination  given  by  the 
catalogue.  If  the  observed  declination  exceeds  the  true, 
the  pole  of  the  instrument  is  above  the  pole  of  the 
heavens,  and  vice  versa,  and  must  be  adjusted  accordingly. 

2.  To  make  the  index  of  the  declination  circle  point  to  o° 
when  the  telescope  points  to  the  celestial  equator. 

Take  the  difference  of  the  two  readings  obtained  in 
the  first  adjustment,  and  divide  it  by  2  ;  this  will  be  the 
index  error  of  the  declination  verniers,  and  they  must  be 
moved  to  correct  it  unless  the  error  is  extremely  small, 
when  it  had  better  simply  be  allowed  for  in  observation. 

3.  To  set  the  polar  axis  in  the  meridian. 

Point  the  telescope  to  some  known  star  about  six  hours 
east  or  west  from  the  meridian  and  as  nearly  midway  as 
possible  between  the  pole  and  the  horizon.  Read  the 
declination  circle  (correcting  for  refraction  if  practicable, 
although  this  is  hardly  necessary  for  an  amateur's  pur- 
poses, unless  great  accuracy  is  desired),  and  compare  the 
result  with  the  value  assigned  in  the  latest  catalogue 
accessible.  If  the  star  is  east  of  the  meridian,  and  its 
observed  declination  exceeds  that  given  in  the  catalogue, 
the  lower  end  of  the  polar  axis  will  be  to  the  west  of  its 
true  place  and  must  be  moved  accordingly.  Should  the 
observed  declination  be  less  than  that  given  in  the  cata- 
logue, the  lower  end  of  the  polar  axis  is  to  the  east  of  its 
true  place. 

Should  the  star  observed  be  west  of  the  meridian,  the 
effects  of  the  erroneous  position  and  the  adjustments  for 
correcting  it  will  be  reversed. 


THE    AMATEUR    TELESCOPIST'S   HANDBOOK.  35 

4.  To  make  the  index  of  the  hour-circle  point  to  o°  when 
the  telescope  is  in  the  meridian. 

If  the  foregoing  adjustments  have  been  carefully  made, 
this  last  one  will  be  found  to  have  been  involved  in  them. 
The  declination  axis  may  be  set  horizontal  by  means  of  a 
level,  and  the  verniers  of  the  hour-circle  set  to  zero. 

There  are  two  methods  of  using  the  equatorial.  In  the 
first,  a  clock  or  watch  set  to  sidereal  time  is  necessary. 
Any  clock  may  be  made  to  serve  this  purpose  for  the  ama- 
teur, the  difference  between  the  rate  of  a  clock  keeping 
sidereal  time  and  one  .keeping  mean  time  being  of  little 
moment  in  one  evening's  work.  The  student  may,  how- 
ever, regulate  his  clock  to  sidereal  time,  if  he  choose,  by 
causing  it  to  gain  3m.  553.  in  twenty-four  hours.  Before 
beginning  observations  the  clock  should  be  set  to  sidereal 
time  in  the  following  manner :  Turn  the  adjusted  tele- 
scope to  some  known  star  east  of  the  meridian,  and  read 
on  the  hour-circle  its  distance  from  the  meridian.  Sub- 
tract this  reading  from  the  star's  right  ascension,  and  the 
result  will  give  the  sidereal  time  with  sufficient  accuracy 
for  our  purpose,  and  the  clock  may  be  set  to  mark  it.  Of 
course,  the  student  will  remember  that  a  sidereal  clock 
indicates  twenty-four  hours  to  the  day,  while  a  mean-time 
clock  indicates  twice  twelve.  If  the  sidereal  time  exceeds 
twelve  hours,  the  observer  may  simply  subtract  twelve 
from  it  and  set  his  clock  accordingly. 

In  case  the  star  used  in  setting  the  clock  is  west  of 
the  meridian,  the  circle  reading  is  to  be  added  to  the  right 
ascension  of  the  star  to  obtain  the  sidereal  time. 

Of  course,  in  all  these  observations  for  adjustment,  etc., 
the  telescope  is  to  be  pointed  toward  the  star  so  that  the 
latter  shall  appear  in  the  centre  of  the  field.  This  is 
most  conveniently  accomplished  by  the  aid  of  a  positive 


36  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

eyepiece  with  crossed  wires  in  its  focus ;  but  this  is  not 
necessary. 

Let  us  take  an  illustration  of  this  method  of  using  the 
equatorial.  Suppose  we  wish  to  find  the  superb  red  star 
R  Leporis.  We  find  from  our  catalogue  that  the  right 
ascension  of  this  star  is  4h.  54m.  365.,  and  its  declina- 
tion 14°  58.2'  south  ;  and  we  will  suppose  that  our  clock 
indicates  6h.  56m.  sidereal  time.  Since  the  right  ascen- 
sion of  the  star  is  greater  than  the  sidereal  time  (which 
expresses  the  right  ascension  of  any  object  at  that  instant 
on  the  meridian),  we  see  that  the  star  has  not  yet  reached 
the  meridian.  Accordingly  we  subtract  the  sidereal  time 
from  the  right  ascension  of  our  star,  and  find  that  the  lat- 
ter is  2h.  im.  245.  east  of  the  meridian.  This  is  called 
the  hour  angle.  The  telescope  is  now  turned  to  the  east 
and  set  to  indicate  this  distance  from  the  meridian  on  the 
hour  circle.  Then  setting  the  declination  circle  to  14° 
58.2'  south,  the  star  should  be  seen  in  the  field. 

If  the  right  ascension  of  an  object  be  less  than  the 
sidereal  time,  it  is  evident  that  the  object  is  west  of  the 
meridian,  and  the  hour  angle  will  be  found  by  subtracting 
the  right  ascension  from  the  sidereal  time. 

The  second  method  of  using  the  equatorial  is  simpler 
and  more  convenient  for  the  amateur,  inasmuch  as  no 
clock  is  required,  although  it  involves,  perhaps,  a  little 
more  trouble  in  circle-reading.  Select  some  known  star 
visible  to  the  naked  eye,  and  note  the  difference  between 
its  right  ascension  and  that  of  the  required  star.  If  the 
right  ascension  of  the  known  star  is  greater  than  that  of 
the  required  star,  the  latter  will  be  west  of  the  former, 
and  vice  versd.  Direct  the  telescope  to  the  known  star, 
and  read  the  hour  circle.  Now  move  it  east  or  west,  as 
the  case  may  be,  until  the  index  of  the  hour  circle  has 


THE    AMATEUR    TELESCOPIST*S   HANDBOOK.  37 

measured  an  arc  equivalent  to  the  difference  of  right 
ascensions.  Set  the  declination  circle,  and  the  required 
star  should  be  found  in  the  field.  It  will  be  found  best 
to  select  the  known  star  on  the  same  side  of  the  meridian 
as  the  required  one,  as  the  reading  of  the  hour  circle  will 
be  less  troublesome. 

If  the  equatorial  be  not  provided  with  a  clamp  in  right 
ascension  (/>.,  to  the  polar  axis),  it  will  usually  be  well  to 
set  and  clamp  the  telescope  in  declination  before  turning 
it  on  its  polar  axis. 

The  success  of  observations  with  the  equatorial  will 
depend  on  the  accuracy  with  which  the  adjustments 
have  been  made,  and  it  is  always  best  with  a  portable 
equatorial  to  put  on  the  lowest  power  when  seeking  an 
object,  so  as  to  embrace  as  large  a  field  as  possible.  A 
little  practice  and  care  will  enable  the  observer  to  adjust 
his  equatorial  expeditiously  and  with  sufficient  accuracy 
for  an  amateur's  purposes.  A  star  may  be  followed  with 
an  equatorially  mounted  telescope  by  simply  turning  the 
instrument  on  its  polar  axis.  An  equatorial  stand  is 
usually  provided  with  an  appliance  to  give  this  slow  move- 
ment in  right  ascension,  consisting  of  a  crown  or  lantern 
wheel  working  upon  the  polar  axis  and  provided  with  a 
universal  joint  from  which  a  rod  leads  to  the  observer's 
hand.  In  the  more  elaborate  and  expensive  equatorial 
stands,  clock-work  is  provided  to  move  the  telescope  in 
right  ascension  at  a  rate  corresponding  to  that  of  the 
apparent  motion  of  celestial  objects. 

The  prices  of  portable  equatorial  stands  are  given  else- 
where, but  the  amateur  will  find  a  description  of  a  simple 
stand,  which  he  can  make  himself,  or  have  constructed 
under  his  own  supervision,  in  the  Astronomical  Register,  vol. 
xiv.,  p.  35.  A  common  equatorial  may  be  made  much 


3§  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

more  effective  by  having  attached  to  it  plain  metal  circles 
or  even  stout  pasteboard  ones,  graduated  by  the  observer 
himself.  The  student  who  is  acquainted  with  the  ex- 
quisite graduation  of  modern  astronomical  circles  may 
feel  dismayed  at  the  suggestion  of  graduating  circles  for 
himself  ;  but  I  can  assure  him  that  with  patience  and  care 
he  can  prepare  circles  which,  if  they  will  not  enable  him 
to  hit  exactly  upon  an  object,  will  greatly  help  him  in 
finding  it. 


CHAPTER   IV. 

ACCESSORIES   OF    THE    TELESCOPE. 

THERE  are  but  few  of  the  supplementary  instruments 
used  in  modern  astronomy  which  are  applicable  to  a 
small  telescope  without  clock-work  to  drive  it.  Micro- 
metric  measurements,  celestial  photography,  and,  except  in 
a  very  limited  degree,  spectroscopic  work,  must  be  left  to 
those  fortunate  ones  who  possess  telescopes  of  larger  size 
and  more  perfect  mounting  than  the  average  amateur  can 
procure.  There  are  two  accessories,  however,  which  every 
telescope  should  possess.  These  are  a  finder  and  a  dew-cap. 
When  observing  with  high  powers,  it  is  a  matter  of  very 
considerable  difficulty  to  fix  the  telescope  upon  any  object. 
Practice  will  diminish  the  difficulties  of  this  operation, 
but  not  sufficiently  to  prevent  the  task's  being  tedious 
and  vexatious.  The  finder  relieves  this  trouble  at  once. 
It  is  a  small  telescope  of  low  power,  and  consequently  of 
large  field,  attached  to  the  telescope  at  its  eye-end,  and 
parallel  with  it.  It  is  so  adjusted  that  any  object  to  which 
the  telescope  is  pointed  will  appear  at  once  in  the  centre 
of  its  field  and  that  of  its  finder.  To  fix  the  telescope 
upon  any  object,  all  we  have  to  do  is  to  set  the  instrument 
so  that  the  object  is  visible  in  the  centre  of  the  finder's 
field,  which  is  effected  with  the  greatest  ease,  and  then, 
if  the  adjustments  have  been  properly  made,  the  star  will 
be  seen  in  the  centre  of  the  telescope's  field,  no  matter 
how  high  may  be  the  power  of  the  eyepiece. 

The  place  of  an  object  invisible  to  the  naked  eye  or  in 


40  THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

the  finder  is  often  given  by  its  position  with  reference  to 
certain  visible  stars.  It  frequently  happens  that  these 
guiding  stars  may  be  visible  in  the  finder,  and  the  tele- 
scope may  be  readily  set  to  the  proper  point  by  the  aid 
thus  afforded. 

The  amateur  need  go  to  little  expense  to  secure  a 
finder  amply  sufficient  for  his  needs.  A  telescope  of  my 
own  is  fitted  with  a  small  toy  "  spy-glass  "  costing  fifty 
cents,  which  serves  its  purpose  as  a  finder  to  perfection. 
Mr.  Proctor  suggests*  that  the  amateur  may  make  his 
own  finder  by  fastening  on  the  two  ends  of  a  pasteboard 
tube  two  lenses  at  a  distance  from  each  other  equal  to  the 
sum  of  their  focal  lengths,  the  object  glass  of,  say,  six 
or  eight  inches  focal  length,  and  the  eye-lens  of  one  or 
two,  giving  a  power  of  from  three  to  eight,  according  to 
the  lenses  used.  This  little  contrivance  is  fastened  to  the 
telescope  tube  with  wires  and  adjusted  each  night  before 
beginning  observations,  by  first  bringing  a  star  to  the 
centre  of  the  telescope's  field  with  a  low  power,  and  then 
setting  the  finder  so  that  the  star  appears  at  the  same  time 
in  the  centre  of  its  field.  "  A  card  tube  with  wire  fasten- 
ings," says  Mr.  Proctor,  "such  as  we  have  described,  may 
appear  a  very  insignificant  contrivance  to  the  regular 
observer  with  his  well-mounted  equatorial  and  carefully 
adjusted  finder.  But  to  the  first  attempts  of  the  amateur 
observer  it  affords  no  insignificant  assistance,  as  I  can 
aver  from  my  own  experience.  Without  it — a  superior 
finder  being  wanting — our  '  half -hours '  would  soon  be 
wasted  away  in  that  most  wearisome  and  annoying  of  all 
employments,  trying  to  '  pick  up  '  celestial  objects." 

Another  necessity  to  the  telescopist  who  makes  out- 

*  Half-hours ,  p.  2O. 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK. 


door  observations  is  a  dew-cap.  Glass  is  an  excellent 
radiator  of  heat,  and  the  atmosphere  quickly  deposits  dew 
upon  it — an  effect  from  which  an  object  glass  needs  pro- 
tection. The  dew-cap  is  a  device  to  afford  this  protection, 
and  is  furnished  regularly  by  some  makers  with  every 
telescope.  It  consists  of  a  tube  of  metal  or  pasteboard 
blackened  inside  and  placed  over  the  objective  end  of  the 
telescope  so  as  to  project  from  eight  to  twelve  inches 
beyond  the  object  glass.  The  amateur  can  easily  make 
this  for  himself  and  should  invariably  use  it  when  observ- 
ing out  of  doors. 

An  instrument  known  as  the  diagonal  eye-tube  is  some- 
times used  for  observing  objects  at  high  altitudes.  This 
consists  of  two  tubes  set  at  right  angles  with  each  other 
and  containing  at  the  elbow  either  a  reflector  of  speculum 
metal  or,  what  is  infinitely  bet- 
ter, a  right-angled  prism. 

The  rays  from  the  object  are 
reflected  (with  great  loss  of 
light)  from  the  mirror  at  AB,  or 
(with  scarcely  any  loss  of  light)  D 
from  the  longest  side  of  the 
right-angled  prism  ABC,  and 
viewed  by  the  eye-piece  at  D,  in 
the  usual  manner.  The  diago- 
nal eye-tube  is  not  to  be  confounded  with  the  diagonal 
eye-piece,  in  which  the  change  of  direction  of  the  light  is 
accomplished  between  the  lenses  of  the  eye-piece. 

This  contrivance  will  be  found  very  useful  for  observ- 
ing objects  near  the  zenith,  or  indeed  at  any  elevation 
above  fifty  or  sixty  degrees. 


CHAPTER   V. 

THE   CARE    OF    THE   TELESCOPE. 

As  a  valuable  and  delicate  instrument  the  telescope 
demands,  and  should  receive,  the  most  solicitous  care. 
In  particular  does  the  object  glass  require  the  most  ten- 
der treatment.  It  should  be  kept  covered  with  its  cap 
whenever  it  is  not  in  actual  use  ;  the  dew-cap  should 
never  be  forgotten  ;  and  the  glass  should  never  be  brought 
from  a  cold  into  a  warm  atmosphere  without  first  cover- 
ing it  to  prevent  its  becoming  bedewed.  If  the  damp 
gets  between  the  glasses  it  will  produce  a  fog — a  sweat, 
in  optician's  language — and,  according  to  Proctor,  even  a 
seaweed-like  vegetation,  by  which  a  valuable  glass  may 
be  ruined.  Should  any  moisture  unluckily  get  upon  the 
object  glass,  the  telescope  must  be  put  in  a  warm  place 
until  the  enemy  has  fled. 

When  it  is  necessary  to  clean  the  object  glass — and  it 
should  only  be  touched  when  cleaning  is  necessary — a 
soft  camel's-hair  brush  should  first  be  used  for  removing 
the  coarser  particles  of  dust,  which  may  be  followed  by  a 
very  careful  sweeping  with  either  a  piece  of  very  fine  clean 
chamois-skin,  or,  better  still,  an  old  soft  silk  handkerchief. 
Mr.  Chambers  prefers  an  old  but  fine  cambric  handker- 
chief. Mr.  Franks  recommends  soft  tissue  paper  aided 
by  the  breath.  A  little  space  near  the  edge  of  the  glass 
is  first  cleaned,  and  from  that  point  the  dust  is  gently 
swept  away.  But  let  it  be  noted  that  a  few  specks  of  dust 
are  of  much  less  moment  than  irremediable  scratches,  and 


THE  AMATEUR  TELESCOPIST'S  HANDBOOK.         43 

polished  optical  glass  scratches  very  easily.  Should  any 
"  refractory  stains  "  get  upon  the  object  glass,  they  may 
be  removed  by  a  few  drops  of  alcohol  on  perfectly  clean 
absorbent  cotton  ;  but,  as  Mr.  Chambers  dryly  observes, 
a  careful  observer  will  never  allow  any  refractory  stains 
to  get  upon  his  object-glass.  Should  fine  dust  ever  cake, 
as  it  sometimes  will,  upon  the  glass,  breathe  on  it  and 
wipe  very  gently  from  the  edges  with  a  soft  cloth,  which 
is  then  thrown  away.  This  may  sound  alarming,  but  it  is 
the  precept  of  no  less  high  an  authority  than  Sir  Howard 
Grubb. 

Everything  used  for  cleaning  lenses  should  be  kept  in 
a  tightly  closed  box  when  not  in  use,  to  preserve  it  from 
dust. 

Never  touch  the  polished  surface  of  any  lens  with 
your  fingers.  The  insensible  perspiration,  always  present 
in  small  quantities,  appears  to  have  a  corroding  effect 
upon  optical  glass,  and  will  destroy  its  polish. 

All  of  the  foregoing  remarks  as  to  cleaning  lenses  apply 
to  eyepieces  as  well  as  to  object  glasses.  Particularly 
must  it  be  remembered  that  every  scratch  or  speck  on 
the  field-glass  of  a  negative  eyepiece  will  appear  in  a 
magnified  form  on  looking  through  the  eyeglass.  Eye- 
pieces should  be  kept,  when  not  in  use,  in  a  dust-tight 
box  ;  one  provided  with  compartments  is  by  far  the  best. 

Under  no  circumstances  should  the  two  glasses  com- 
posing the  objective  be  separated  or  taken  out  of  their 
cell  by  the  amateur.  Should  circumstances  make  it  nec- 
essary to  separate  them,  let  it  be  done  by  the  maker  or 
by  a  competent  optician  :  otherwise  the  glass  may  be 
rendered  worthless.  Another  rule,  with  an  example,  is 
given  by  Mr.  Proctor,  which  I  will  quote  in  his  own 
vigorous  language :  "  Suffer  no  inexperienced  person  to 


44  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

deal  with  your  object  glass.  I  knew  a  valuable  glass 
ruined  by  the  proceedings  of  a  workman  who  had  been 
told  to  attach  three  pieces  of  brass  round  the  cell  of  the 
double  lens.  What  he  had  done  remained  unknown  ;  but 
ever  after  a  wretched  glare  of  light  surrounded  all  objects 
of  any  brilliancy." 

Should  the  brass-work  of  the  telescope  or  stand  become 
dull  or  dirty,  it  may  be  cleansed  with  a  piece  of  chamois- 
skin  moistened  with  sweet-oil.  Care  should  be  taken  in 
cleaning  an  equatorial  stand,  not  to  press  hard  upon  the 
circles  lest  they  be  bent  out  of  "true."  For  protecting 
bright  metal  surfaces  from  oxidation,  and  also  for  lubri- 
cating purposes,  ordinary  vaseline  is  by  far  the  best 
preparation,  as  it  is  free  from  the  gumminess  which  is  apt 
to  attach  to  common  oils. 


CHAPTER   VI. 

THE    USE    OF    THE    TELESCOPE. 

THE  amateur  who  possesses  no  observatory  will  find  it 
by  far  the  best  plan  to  make  all  his  observations  out  of 
doors.  If  a  telescope  is  mounted  in  a  house,  the  move- 
ment of  any  person  about  any  part  of  the  building  will 
cause  the  instrument  to  vibrate,  especially  when  high 
powers  are  in  use.  In  regular  observatories  it  is  cus- 
tomary to  mount  the  equatorial  on  a  pier  of  solid  ma- 
sonry to  prevent  this  very  difficulty.  Moreover,  when 
the  telescope  is  used  at  a  window,  the  observer  will  be 
troubled  greatly  by  a  wavering  of  the  atmosphere  before 
the  object  glass.  This  annoyance  will  be  considerably 
lessened  if  the  temperature  of  the  room  is  the  same  as 
that  of  the  outer  air,  but  such  a  condition  is  not  easily 
attained. 

Observations  of  all  celestial  objects,  except  those  so 
near  the  horizon  that  the  observer  can  stand  upright  when 
viewing  them,  should  be  made  while  comfortably  seated ; 
and  this  not  so  much  for  comfort's  sake  as  for  clearness 
of  vision.  There  is  no  doubt  that  a  constrained  or  un- 
comfortable position  decidedly  affects  the  power  of  the 
eye  in  telescopic  work.  Specially  constructed  observing 
chairs  are  in  use  in  observatories,  but  the  amateur  will 
need  only  a  common  chair  and  a  stool.  A  small  but 
strong  step-ladder  will  also  prove  useful. 

I  must  not  omit  to  warn  the  reader  of  the  importance 
of  being  warmly  clad  for  out-door  observation  in  winter. 


46  THE    AMATEUR    TELESCOPIST'S   HANDBOOK. 

The  use  of  the  telescope  involves  little  bodily  motion  ; 
while  looking  through  it  the  whole  person  is  kept  as  still 
as  possible  ;  and  the  result  is  that  a  temperature  which 
would  be  regarded  as  mild  for  a  walk  may  chill  the  body 
thoroughly  in  a  short  time  while  at  work  with  the  tele- 
scope. A  severe  and  perhaps  dangerous  cold  may  thus  be 
taken.  So  let  the  observer  on  all  winter  nights,  and  on  a 
very  large  proportion  of  spring  and  autumn  ones,  put  on 
his  heaviest  great-coat,  and  if  the  ground  be  at  all  damp, 
overshoes  as  well.  I  wish  to  impress  the  student  with 
the  importance  of  these  precautions. 

Should  artificial  light  be  needed  for  consulting  a  book 
or  map,  or  for  looking  at  the  circles  of  an  equatorial,  the 
observer  should  use  a  bull's-eye  lantern  with  a  slide,  as 
he  is  thus  enabled  to  throw  a  light  on  the  object  without 
dazzling  his  eyes,  and  the  light  may  be  cut  off  with  the 
slide  when  not  needed.  It  is  a  good  plan  to  cover  the 
bull's-eye  with  a  piece  of  thin  red  silk  or  red  paper,  since 
red  light  is  less  trying  to  the  eyes  than  white.  A  very 
good  substitute  for  the  bull's-eye  lantern  is  a  little  flat  tin 
lantern  with  a  red  glass  front  and  having  a  door  by  which 
all  light  may  be  cut  off.  Such  a  lantern  is  commonly  sold 
by  dealers  in  photographic  materials. 

The  novice  is  apt  to  assume  that  a  clear  bright  night  is 
necessarily  the  best  for  telescopic  work,  but  such  is  not 
always  the  case.  Some  brilliant  nights,  while  available 
for  good  work  on  the  nebulae,  are  characterized  by  very 
poor  definition,  and  are  practically  worthless  for  observa- 
tions on  the  planets  and  double  stars.  This,  I  think,  may 
be  especially  noted  with  regard  to  Saturn,  whose  rings  I 
have  seen  go  through  the  most  extraordinary  gyrations  on 
an  apparently  superb  night.  On  the  other  hand,  a  hazy 
night  often  gives  very  beautiful  definition,  especially  in 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  47 

the  case  of  the  planets.  A  remarkable  instance  of  this  is 
the  discovery  by  Professor  Bond  of  the  inner  dusky  ring 
of  Saturn  on  a  night  so  hazy  that  none  but  the  larger 
stars  were  visible  to  the  naked  eye. 

Several  devices  are  at  times  made  use  of  for  improving 
the  defining  power  of  the  object  glass  when  employed 
upon  close  double  stars  or  other  objects  needing  particu- 
larly good  definition.  One  of  these  is  to  "  stop  down  " 
the  glass  ;  in  other  words,  to  diminish  its  aperture  by 
means  of  a  screen  of  cardboard  or  similar  material 
pierced  with  a  circular  opening  of  the  desired  size.  This 
is  sometimes  particularly  useful  in  observing  Venus. 
Another  device,  recommended  by  Sir  John  Herschel,  is 
to  fix  a  disk  of  cardboard  having  a  diameter  of  from  one- 
fifth  to  one-half  that  of  the  object  glass  centrally  in  front 
of  the  glass.  This  will  increase  the  separating  power  of 
the  objective,  and  will  be  occasionally  useful,  although  it 
increases  both  the  number  and  the  breadth  of  the  diffrac- 
tion rings  around  the  image.  Mr.  Dawes  recommends  his 
own  curious  plan  of  covering  the  whole  object  glass  with 
perforated  cardboard  such  as  is  (or  was)  employed  for 
worsted  work  ;  or,  should  the  object  be  too  faint  to  bear 
such  treatment,  with  a  piece  of  cardboard  pierced  with 
circles  of  equal  size  (about  one-fifth  of  an  inch  in  diam- 
eter), arranged  in  concentric  circles. 

All  these  contrivances  may  be  useful  at  times,  but  as  a 
general  rule  the  possessor  of  a  small  telescope  cannot 
afford  to  lose  any  light. 

To  get  the  eye  in  condition  for  use  at  the  telescope,  it 
is  well  for  the  observer  to  remain  in  the  dark  for  some 
little  time  before  beginning  work.  If  after  some  time 
spent  in  observation  it  is  desired  to  scrutinize  a  difficult 
object,  it  will  be  very  useful  to  turn  the  eyes  toward  a 


48  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

dark  place,  or  cover  them  with  the  hand  for  a  time,  to 
permit  the  pupils  to  dilate.  An  instance  of  the  ad- 
vantages of  this  plan  is  the  rediscovery  by  Sir  John 
Herschel  of  the  satellites  of  Uranus,  which  he  accom- 
plished after  keeping  his  eyes  in  darkness  for  a  quarter 
of  an  hour.* 

If  the  stand  of  a  telescope  is  at  all  unsteady,  it  is  an 
excellent  plan  to  point  the  instrument  not  directly  on  the 
object  that  is  to  be  viewed,  but  a  field,  or  even  two,  pre- 
ceding the  object,  and  allow  the  diurnal  motion  of  the 
earth  to  carry  the  image  across  the  field.  This  will  per- 
mit the  telescope  to  settle  down  into  perfect  steadiness 
before  the  object  comes  in  view.  The  finder  will  afford 
great  help  in  carrying  out  this  expedient 

A  word  should  be  said  concerning  the  focusing  of  the 
telescope.  The  usual  method  with  novices  is  to  turn  the 
rack-button  slowly  until  the  image  appears  sharp.  As  a 
result  it  is  hardly  ever  turned  enough,  and  the  eye  is 
strained.  The  proper  way  is  to  turn  the  button  back  and 
forth,  bringing  the  eye  piece  decidedly  outside  and  inside 
of  the  focus  each  time  ;  and  after  a  few  turns  it  will  be 
found  that  a  certain  degree  of  turning  brings  it  equally 
on  each  side  of  the  focus.  Make  the  object  equally  indis- 
tinct on  both  sides,  and  give  a  half  turn,  which  brings  the 
eye  piece  to  the  true  focus.  Practice  will  speedily  make 
perfect  in  this  operation. f 

The  beginner  with  the  telescope  is  very  apt  to  make 
the  same  mistake  as  does  the  beginner  with  the  micro- 
scope, and  that  is  in  a  tendency  to  use  too  high  powers. 
In  examining  very  close  doubles  a  high  power  must,  of 
course,  be  used  ;  the  same  is  true  of  the  more  minute 

*  Proctor.  -J-  Sir  Howard  Grubb. 


THE    AMATEUR    TELESCOPIST's    HANDBOOK. 


49 


study  of  the  planets  ;  but  for  all  other  observations  a 
lower  power  is  far  better.  A  high  power,  moreover, 
brfngs  out  all  defects  in  the  object  glass,  the  stand,  and 
the  state  of  the  atmosphere  ;  and  the  field  is  made  so 
small  that  the  object  passes  very  quickly  out  of  it  by  the 
rotation  of  the  earth.  An  object  sends  a  certain  amount 
of  light  through  the  telescope,  and  magnifying  any  object 
having  an  apparent  diameter  lessens  its  light,  since  it 
spreads  the  image  over  a  larger  space.  For  this  reason 
powers  beyond  a  certain  limit  are  perfectly  useless  in  the 
examination  of  nebulae.  Hints  as  to  the  powers  to  be 
employed  in  particular  cases  will  be  given  further  on,  and 
the  reader  is  referred  to  Chapter  I.  for  a  table  of  the 
highest  powers  that  should  be  commonly  used  with  given 
apertures. 

Familiarity  with  the  constellations  is,  of  course,  a 
requisite  of  the  first  importance  in  an  astronomer  ;  and  it 
is  believed  that  the  arrangement  adopted  in  this  book,  of 
grouping  the  telescopic  objects  of  the  heavens  according 
to  the  asterisms  in  which  they  appear,  will  conduce 
greatly  to  a  full  and  satisfactory  study  of  the  constella- 
tions singly.  A  set  of  good  star-maps  is  perhaps  the 
very  first  book  that  the  astronomer  needs.  For  merely 
the  delineations  of  the  constellations  and  the  relative 
positions  of  the  stars,  any  of  the  standard  maps  will  be 
sufficient  :  Hind's,  in  Keith  Johnson's  Atlas  of  Astron- 
omy, the  Royal  Astronomical  Society's  maps,  those  pub- 
lished by  the  Society  for  the  Diffusion  of  Useful  Knowl- 
edge, and  Heis's  Neuer  Himmels  Atlas  are  all  of  the  high- 
est class.  The  well-known  and  inexpensive  maps  accom- 
panying Burritt's  Geography  of  the  Heavens  are  also 
fairly  good.  But  for  locating  the  planets  in  their  course, 
4 


50  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

either  for  purposes  of  study  or  (in  the  case  of  Uranus 
and  Neptune)  for  telescopic  observation,  the  above  maps 
are  not  suited,  since,  owing  to  precession,  they  are  out  "of 
date.  I  therefore  recommend  the  student  to  supply  him- 
self with  R.  A.  Proctor's  admirable  maps  or  Klein's  Star 
Atlas,  recently  published  by  the  Society  for  Promoting 
Christian  Knowledge.  This  latter  is  a  work  of  much 
value,  although  unsuited  for  consultation  by  lantern 
light,  since  the  lettering  and  numbering  of  the  stars, 
etc.,  and  the  names  and  boundaries  of  the  constellations 
are  printed  in  a  faint  red.  Both  Proctpr's  and  Klein's 
Atlases  are  constructed  for  the  year  1880,  and  will  remain 
sufficiently  accurate  for  our  use  for  twenty  or  thirty  years 
to  come. 

In  studying  the  constellations  the  observer  should  ac- 
custom himself  to  estimate  by  the  eye  distances  in  degrees 
on  the  celestial  sphere.  There  are  three  standards  of 
measurement  provided  in  the  heavens.  The  length  of 
the  belt  of  Orion  is  (speaking  roughly)  three  degrees ; 
the  distance  from  a  to  /3  Ursse  Majoris  (the  well-known 
"  Pointers  ")  is  five  degrees  ;  and  the  average  apparent 
diameter  of  the  moon  is  half  a  degree.  By  practice  the 
observer  will  soon  acquire  the  power  of  measuring  dis- 
tances by  these  celestial  measuring-rods  with  very  con- 
siderable accuracy. 

If  the  student  is  at  all  near-sighted  (as  most  modern 
students  are),  he  will  find  it  very  helpful  and  pleasant  to 
use  an  opera-glass  in  studying  the  constellations.  I  al- 
ways make  use  of  a  binocular  field-glass  of  one  and  seven- 
eighths  inches  aperture  and  embracing  a  field  about  four 
degrees  in  diameter.  The  larger  clusters — the  Pleiades, 
the  Hyades,  Praesepe,  and  Coma  Berenices — are  peculiarly 
beautiful  in  such  a  glass  ;  and  no  one  who  has  not  tried 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  51 

this  method  of  studying  a  constellation  can  imagine  the 
pleasure  and  ease  afforded  by  it.* 

Better  than  star-maps  for  some  reasons  is  a  good  mod- 
ern celestial  globe.  With  this  classic  instrument  the 
student  can  perform  many  problems  which  are  of  impor- 
tance to  him  in  his  astronomical  work,  such  as  ascertain- 
ing quickly  and  easily  the  time  of  the  rising,  culmination, 
and  setting  of  any  star  or  planet,  and  the  accurate  locat- 
ing of  any  telescopic  object  which  may  not  be  marked 
upon  the  globe.  The  little  machine  known  as  Whitall's 
Planisphere,  while  of  small  merit  as  a  map,  will  also  be 
found  very  useful,  provided  the  observer  does  not  live  too 
far  away  from  the  latitude  for  which  the  Planispehre  is 
especially  adapted,  namely,  4o°-5o°. 

Next  in  importance  to  the  star-maps  among  the  astron- 
omer's working  books  is  an  Ephemeris.  Many  of  the 
popular  almanacs  contain  much  useful  astronomical  mat- 
ter ;  but  I  strongly  recommend  the  student  to  procure 
the  Nautical  Almanac  of  his  own  country.  This  gives  in- 
formation that  is  invaluable  to  the  astronomer  :  the  posi- 
tion of  the  sun,  moon,  and  planets  for  every  day  of  the 
year,  the  eclipses  and  occultations  for  the  year,  the  posi- 
tions of  Jupiter's  satellites  for  every  day,  etc. ;  in  short, 
all  the  phenomena  which  can  profitably  occupy  the  atten- 
tion of  the  telescopist. 

*  See  Mr.  Serviss's  pleasant  little  book,  Astronomy  with  an 
Opera-glass. 


CHAPTER   VII. 

OBSERVATION. STARS,    NEBULA,    THE    SUN   AND    MOON. 

THE  tyro  must  remember  that  successful  observation 
with  the  telescope  requires  practice  and  a  certain  training 
of  the  eye.  It  is  not  at  all  unlikely  that  he  may  ex- 
perience some  disappointment  at  the  outset  of  his  work 
by  failing  to  see  objects  which  he  has  been  taught  will 
be  visible  with  such  an  aperture  and  such  powers  ;  and 
also  by  the  difference  between  what  he  may  expect  to  see 
and  what  he  actually  does  see.  Let  him  not  be  dis- 
heartened, nor  let  him  hastily  condemn  his  telescope;  but 
rather  let  him  persevere,  practising  on  the  easier  doubles 
and  the  more  conspicuous  nebulae  ;  and  he  will  find  that 
in  a  comparatively  short  time  he  will  be  able  to  detect 
objects  of  a  minuteness  and  faintness  which  would  have 
rendered  them  quite  invisible  to  him  at  first.  On  this 
subject  I  again  refer  the  reader  to  Sir  Howard  Grubb's 
remarks  in  Chapter  II. 

The  eye  should  be  steadily  fixed  on  the  object  under 
observation  ;  and  it  will  be  noticed  that  details  will  fre- 
quently come  out  at  intervals  which  are  indistinct  or  even 
invisible  in  the  mean  time.  This  may  be  especially  noted 
of  the  belts  of  Jupiter  and  Saturn  when  working  with  a 
small  aperture. 

In  scrutinizing  a  difficult  object  it  will  sometimes  be 
found  helpful  for  the  near-sighted  observer  to  take  off 
his  eyeglasses  or  spectacles,  altering  the  focus  of  his 
telescope  to  meet  the  change.  Occasionally  the  slight 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  53 

additional  loss  of  light  caused  by  another  glass  between 
the  eye  and  the  image  may  just  prevent  the  sight  of  an 
object  which  will  become  visible  when  the  glass  is  re- 
moved. I  have  several  times  experienced  this  when  ob- 
serving nebulae. 

A  very  minute  star  may  often  be  seen  by  directing  the 
eye  not  directly  upon  it,  but  to  another  quarter  of  the 
field  ;  the  little  star  is  thus  seen  out  of  the  corner  of 
the  eye,  so  to  speak.  This  familiar  fact  proves  very  use- 
ful in  the  perception  of  very  small  comites. 

I  append  certain  directions  which  the  observer  will 
note  with  regard  to  observations  upon  different  celestial 
objects.  It  is,  of  course,  not  within  the  purpose  of  this 
little  work  to  treat  minutely  of  these  objects,  but  only  to 
give  such  points  as  may  be  necessary  to  the  amateur  tel- 
escopist  who  proposes  to  study  them  with  humble  instru- 
mental means. 

THE  [FIXED  STARS. — In  the  lists  given  in  this  book  I 
have  followed  Admiral  Smyth  in  his  estimate  of  the  col- 
ors of  stars  ;  but  I  must  warn  the  student  that  these  state- 
ments concerning  color  are  often  rather  fantastic,  espe- 
cially with  small  apertures,  which  give  much  less  idea  of 
color  in  a  star  than  do  larger  ones.  When  the  judg- 
ments of  observers  have  differed  greatly  on  this  subject, 
I  have  stated  the  opinion  of  the  dissenters  from  Admiral 
Smyth. 

The  powers  to  be  employed  upon  double  stars  will  be 
best  learned  by  experiment.  They  differ  in  proportion  to 
the  distance  and  brilliancy  of  the  components.  Some 
may  be  readily  seen  with  the  lowest  powers,  while  others 
will  demand  the  highest  powers  that  a  small  telescope 
will  bear.  Here,  as  with  other  objects,  the  best  power  to 
use  is  the  lowest  that  will  effectually  do  the  work.  By  a 


54  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

number  of  experiments  Mr.  Dawes  ascertained  that  the 
closest  double  star  which  a  i-inch  glass  could  separate 
was  one  in  which  the  distance  between  the  components 
was  4.56";  and  he  devised  the  following  empirical  form- 
ula for  ascertaining  the  separating  power  of  different 
apertures  : 

Separating  power  in  seconds  of  arc  = ^^—. — : — 

aperture  in  ins. 

The  separating  power  of  different  apertures  would  then 
be  as  follows : 

Least  Separable  Least  Separable 

Aperture.  Distance.  Aperture.         "  Distance. 

a  a 

I  4.56  4  1.14 

1.6  2.85  4.5  i. 01 

2.0  2.28  5.5  O.pT 

2.5  1.82  5.5  0.83 

3.0  1.52  6.0  0.76 

3.5  1.30  6.5  0.70 

Mr.  Chambers  recommends  a  power  of  120  on  a  3-inch 
glass  for  doubles  of  a  distance  from  3"  to  12"  ;  of  240  for 
any  closer  ones  ;  and  of  less  than  120  for  any  doubles  of 
greater  distance  than  12". 

NEBULAE. — These  weird  and  most  fascinating  objects 
must  be  reluctantly  admitted  to  be,  for  their  full  apprecia- 
tion, rather  beyond  the  powers  of  a  small  telescope.  A 
large  light-collecting  power — in  other  words,  a  large 
aperture — is  needed  for  their  satisfactory  study.  But  the 
mere  sight  of  a  nebula  has  a  mysterious  and  awe-inspiring 
charm  about  it ;  and  all  the  nebulae  listed  in  this  book  are 
at  least  visible  with  an  aperture  of  three  inches  at  most. 
Moreover,  there  is  a  singular  circumstance  in  this  connec- 


THE    AMATEUR   TELESCOPIST's   HANDBOOK.  55 

tion,  mentioned  by  d' Arrest ;  which  is  that  a  nebula  is 
sometimes  seen  with  a  small  aperture  which  is  invisible 
with  a  large  one.  M.  d'Arrest  states  that  Tempel's  nebula 
in  the  Pleiades  is  perceptible  in  the  finder  of  the  n-inch 
refractor  at  Copenhagen,  but  invisible  in  the  telescope 
itself.  * 

Low  powers  must  almost  invariably  be  used  upon 
nebulae  ;  every  enlargement  of  these  objects  diminishes 
the  quantity  of  light  available  for  seeing  them. 

THE  SUN. — It  seems  unlikely  that  any  one  of  ordinary 
sense  should  need  to  be  warned  not  to  look  at  the  sun 
through  a  telescope  without  the  employment  of  some 
means  to  protect  the  eye  against  the  blazing  light  of  that 
tremendous  orb.  And  yet  no  less  great  an  astronomer 
than  Sir  William  Herschel  lost  an  eye  by  making  that 
mad  attempt.  So  let  the  student  be  earnestly  admon- 
ished to  take  the  best  precautions  to  shield  his  eyes  when 
engaged  in  solar  observation.  The  plan  commonly 
adopted  is  to  use  the  sun-shades  which  are  usually  fur- 
nished with  eye  pieces,  the  colors  of  which  are  either  neu- 
tral-tint, blue,  or  red.  But  with  an  aperture  of  more  than 
two  inches  there  is  danger  that  if  observation  be  pro- 
longed the  shading  glass  will  crack  and  the  light  of 
the  sun  be  transmitted  with  perhaps  disastrous  effect. 
Red  shades  are  less  liable  to  this  calamity  than  the  blue 
or  neutral  ones,  but  even  they  are  not  altogether  free 
from  danger,  and,  moreover,  a  red  glass  is  not  a  pleasant 
medium  through  which  to  view  the  sun.  The  observer 
may  stop  his  object  glass  down  to  two  inches  or  under, 
or  he  may  turn  the  instrument  away  from  the  sun  at 
short  intervals  to  allow  the  eye  piece  and  the  air  within 

*  Webb,  Celestial  Objects,  p.  399. 


56  THE    AMATEUR   TELESCOPIST's   HANDBOOK. 

the  tube  to  cool  off ;  or  if  he  possesses  a  terrestrial  eye- 
piece, he  may  use  it  for  solar  observations.  The  addi- 
tional lenses  which  this  eyepiece  interposes  between  the 
object  glass  and  the  eye  absorb  some  of  the  light  and 
heat,  and  much  lessen  the  danger  to  the  shade  glass. 
This  is  the  method  recommended  by  Mr.  Proctor,  and  to 
the  advantages  of  which  I  can  bear  testimony.  But  if 
the  observer  proposes  to  devote  much  time  to  the  sun, 
he  will  find  that  one  of  the  forms  of  the  diagonal  solar 
eyepiece  will  repay  him  for  the  expense  incurred  in  its 
purchase.  One  of  these  instruments  consists  essentially 
of  a  perfectly  plane  piece  of  plate-glass  set  at  an  angle  of 
forty-five  degrees  with  the  optical  axis  of  the  telescope, 
so  as  to  reflect  the  sun's  rays  at  a  right  angle  with  that 
axis.  The  under  side  of  this  reflector  is  ground,  in  order 
to  avoid  a  double  reflection,  and  a  very  large  proportion  of 
the  sun's  light  and  heat  passes  through  it.  That  portion 
which  is  reflected  is  viewed  through  an  eyepiece  with  a 
lighter  shade,  set  at  right  angles  with  the  optical  axis.* 

In  another  and  more  commonly  used  solar  diagonal 
eyepiece,  a  front-surface-reflecting  prism  or  wedge  is  sub- 
stituted for  the  plane  reflector.  This  reflects  only  about 
one-thirtieth  of  the  sun's  light,  and  scarcely  any  of  its  heat. 

These  devices  enable  the  observer  to  keep  his  telescope, 
directed  to  the  sun  for  an  indefinite  period. 

Perhaps  the  best  of  all  methods  for  studying  the  sun  is 
simply  to  throw  its  image  upon  a  sheet  of  clean  white 
paper  or  cardboard.  The  ingenious  amateur  will  easily 
contrive  a  method  of  supporting  this  cardboard.  One 
favorite  plan  is  to  make  a  light  cone  or  pyramid  with  its 
small  end  attached  to  the  eye-end  of  the  telescope,  the 

*  Noble,  Three-inch  Telescope,  p.  9. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  57 

framework  being  made  of  stiff  wire  or,  better,  bamboo, 
and  covered  with  black  calico  or  cambric.  The  bottom 
of  this  pyramidal  box  holds  the  cardboard  sheet  on 
which  the  image  is  received.  An  opening  in  the  side  of 
the  pyramid  enables  the  observer  to  see  the  image.  A 
photographer's  focusing  cloth  placed  over  the  observer's 
head  will  keep  off  extraneous  light  and  enable  him  to 
study  with  ease  and  pleasure  the  phenomena  of  the  solar 
surface. 

The  most  prominent  of  these  phenomena  are,  of  course, 
the  spots.  These  are  never,  according  to  Mr.  Howlett, 
less  than  three  seconds  in  length  or  breadth,  and  are  con- 
sequently fully  within  the  grasp  of  a  small  telescope. 
Each  spot  which  can  be  sufficiently  magnified  for  such  a 
purpose  will  be  seen  to  consist  of  a  central  black  portion, 
or  umbra,  surrounded  by  a  region  less  dark,  called  the 
penumbra.  These  spots  are  depressions  or  openings  in 
the  sun's  photosphere,  or  outward  envelope.  Facula  are 
supposed  to  be  elevations  or  ridges  on  the  photosphere. 
They  are  streaks  and  spots  of  light,  usually  in  the  neigh- 
borhood of  dark  spots,  and  are  sometimes  of  very  singu- 
lar form. 

To  catch  the  mottling  or  graining  of  the  solar  surface, 
Captain  Noble  recommends  the  shifting  about  of  the  tele- 
scope so  as  to  cause  the  sun's  image  to  move  about  in  the 
field,  when  "  the  eye  will  soon  receive  the  impression  of  a 
roughness  or  grain  upon  the  sun's  surface,  akin  to  that 
of  a  piece  of  magnified  loaf  sugar." 

THE  MOON. — With  a  sense  of  relief  we  turn  away  from 
the  glare  of  the  sunlight,  with  its  revelation  of  the  com- 
mon things  of  earth,  to  the  quiet  and  mystic  beauty  of 
the  "astronomer's  day."  Our  lovely  satellite  presents 
an  ever  varying  and  ever  interesting  subject  of  study, 


58  THE    AMATEUR    TELESCOPIST*S   HANDBOOK. 

and  I  much  regret  that  the  limits  of  this  book  forbid  as 
full  a  description  of  the  moon  as  I  should  like  to  present 
to  the  reader. 

The  moon  should  be  carefully  scanned  by  the  observer 
as  she  passes  through  her  phases,  and  it  is  recommended 
that  he  try  to  make  two  observations  each  evening,  one 
as  early  and  the  other  as  late  as  possible.  In  this  way  he 
will  be  able  to  observe  the  gradual  creeping  of  the  sun- 
light over  the  craters  and  mountains  of  the  "spotty  globe," 
and  to  note  the  extraordinary  effects  produced  by  the 
gradual  advance  or  retreat  of  the  terminator  or  the  irregu- 
lar line  marking  the  limit  to  which  the  illumination 
reaches.  "  The  outlying  and  isolated  peak  of  some  great 
mountain  chain  becomes  gradually  larger  and  is  finally 
merged  into  the  general  luminous  surface  ;  great  cir- 
cular spaces,  enclosed  with  rough  and  rocky  walls  many 
miles  in  diameter,  become  apparent  ;  some  with  flat  and 
perfectly  smooth  floors  variegated  with  streaks  ;  others 
in  which  the  flat  floor  is  dotted  with  numerous  pits,  or 
covered  with  broken  fragments  of  rock.  Occasionally  a 
regularly  formed  and  unusually  symmetrical  circular  for- 
mation makes  its  appearance,  the  exterior  surface  of  the 
wall  bristling  with  terraces  rising  gradually  from  the 
plain,  the  interior  one  much  more  steep  ;  and  instead  of 
a  flat  floor,  the  inner  space  is  concave  or  cup-shaped  with 
a  solitary  peak  rising  in  the  centre.  Solitary  peaks  rise 
from  the  level  plains  and  cast  their  long,  narrow  shadows 
athwart  the  smooth  surface.  Vast  plains  of  a  dusky  tint 
become  visible,  not  perfectly  level,  but  covered  with 
ripples,  pits,  and  projections.  Circular  wells  which  have 
no  surrounding  wall  dip  below  the  plain,  and  are  met  with 
even  in  the  interior  of  the  circular  mountains  and  on  the 
tops  of  their  walls.  From  some  of  the  mountains  great 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  59 

streams  of  a  brilliant  white  radiate  in  all  directions  and  can 
be  traced  for  hundreds  of  miles.  We  see  again  great 
fissures  almost  perfectly  straight  and  of  great  length, 
although  very  narrow,  which  appear  like  the  cracks  in 
moist  clayey  soil  when  dried  by  the  sun."  * 

The  student  who  desires  to  go  minutely  into  the  study 
of  the  topography  of  the  moon  should  procure  Neison's 
admirable  book  on  this  subject.  For  an  amateur's  pur- 
poses the  brief  study  given  here  may  perhaps  suffice.  An 
excellent  map  of  the  moon  is  given  in  Webb's  Celestial 
Objects  and  maybe  obtained  separately  for  eighteen  pence 
from  Longmans,  Green  &  Co.,  of  London  and  New  York. 
This  map  is  given  in  a  reduced  form  in  Noble's  Three- 
inch  Telescope,  and  from  it  the  guide-map  presented  in 
this  book  is  prepared. 

In  the  following  brief  descriptions  of  lunar  objects  I 
have  simply  used  the  words  above,  below,  right,  left,  etc., 
rather  than  employ  the  points  of  the  compass  according 
to  the  usage  of  selenographers.  It  may  be  well  to  state, 
however,  that  in  maps  of  the  moon  as  seen  in  an  inverting 
telescope  (and  such  is  our  guide-map),  the  North  and 
South  points  occupy  the  bottom  and  top  of  the  map 
respectively,  while  the  East  and  West  points  are  at  the 
right  and  left  respectively,  as  in  terrestrial  maps. 

The  map  represents  the  moon  at  the  period  of  its  mean 
libration,  and  the  expressions  above,  below,  etc.,  must  be 
understood  as  describing  the  relative  positions  of  objects 
at  that  period. 

i.  TYCHO. — We  begin  with  what  Webb  calls  "the  met- 
ropolitan crater  of  the  moon."  This  will  be  instantly 

*  From  a  paper  by  Breen,  in  Popular  Science  Monthly ',  quoted  by 
Proctor,  Half-hours,  p.  93. 


60  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

recognized  as  the  most  conspicuous  object  on  the  face  of 
our  satellite  when  full — a  crater  from  which  radiates  a 
vast  system  of  rills  or  rays  extending  over  at  least  a  quar- 
ter of  the  disk.  It  is  visible  to  a  sharp  eye  without  opti- 
cal aid,  has  a  diameter  of  54^  miles,  and  its  walls  rise  at 
the  highest  point  to  17,000  feet.  Its  central  hill  is  be- 
tween 5,000  and  6,000  feet  high.  To  its  left  is  Pictet,  to 
the  left  of  which  is  Saussure.  To  the  right  of  Tycho  is 
Heinsius.  Above  and  a  little  to  the  left  is  Street,  above 
which  is  Maginus — a  noble  formation  which  utterly  dis- 
appears at  full  moon. 

2.  PLATO. — A     grand     ring-plain     60     miles    across. 
Under  it  extends   the   Mare  Frigoris;  above  it  to  the 
right  is  the  Mare  Imbrium,  and   to   the  left  the  Mare 
Serenitatis.     Plato  was  called  by  Hevelius  the  "  Greater 
Black  Lake,"  and,  with  the  exception  of  Grimaldi,  is  the 
darkest  part  of  the  moon's  surface. 

3.  LINNE. — A   small   crater   in   the   Mare   Serenitatis, 
where  indications  of  recent  volcanic   action  have  been 
thought  to  be  seen  ;  an  opinion  favored  by  Proctor  and 
Webb. 

4.  ARISTARCHUS. — The  most  brilliant   portion   of  the 
moon's  surface.    "  Its  peaks  shine  often  like  stars  when  the 
mountain  is  within  the  unillumined  portion  of  the  moon's 
surface."     (Proctor.)     At  times  "  its  lustre  is  actually  un- 
pleasant  to   the   eye,   even   in   a  three-inch   telescope." 
(Noble.)     Its  central  mountain  seems  even  brighter  than 
the  walls  of  the  crater.     Immediately  to  the  right  of  it 
lies  Herodotus. 

5.  MESSIER. — Two  craters  from  which  extend  two  sin- 
gular straight  streaks,  giving  the   object  an  appearance 
somewhat  like  a  comet,  and  suggesting  its  name  from  the 
famous  French  "comet  ferret,"  M.  Messier. 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  6l 

6.  THE  ALPS. — A  grand  range  of  mountains  strongly 
resembling  terrestrial  systems.     The  chain  is  interrupted 
by  a  vast  valley  between  80  and  90  miles  long,  and  from 
3^  to  6  miles  across. 

7.  THE  APENNINES. — A  magnificent  range  resembling 
that  of  the  Alps,  but  including  higher  peaks,  and  culmi- 
nating in  Mount  Huygens,  20,000  feet  high.     This  chain 
is  one  of  the  portions  of  the  moon  which  frequently  pro- 
ject beyond  the  terminator  so  strikingly  at  times  that  a 
keen  eye  may  perceive  it  without  a  telescope.    The  range 
terminates  in  the  splendid   crater   Eratosthenes.     Above 
and  to  the  left  of  Mount  Huygens  lies  the  mare  called 
Middle  Bay. 

8.  FRASCATORIUS. — A  curious  "  bay  "  at  the  upper  end 
of  the  Mare  Nectaris.     Below  it  and  to  its  right,  on  the 
edge  of  the  mare,  is  Beaumont. 

9.  POSIDONIUS. — One  of  the  largest  ring-plains  on  the 
moon,  62  miles  in  diameter,  with  a  fine  central  crater. 
It   lies   in  the  Mare  Serenitatis,  and  has  a  smaller  ring- 
plain  (Chacornac)  attached  to  it  toward  the  left. 

10.  n,  12.   THEOPHILUS,   CYRILLUS,    CATHERINE. — A 
grand  triple  group.     Study  it  carefully.     Note   the   two 
mountains  in  Cyrillus  and  the  crater  on  its  wall.    The- 
ophilus  is  the  deepest  crater  in  the  moon,  its  wall  rising, 
in  places,  18,000  feet  above  the  bottom.     Its  diameter  is 
about  64  miles,  and  when  the  moon  is  about  five  days  old, 
the  illuminated  portion  of  the  summit  of  Theophilus  is 
projected  beyond  the  terminator  as  a  luminous  ring. 

13,  14, 15.  ARZACHEL,  ALPHONSUS,  PTOLEMY. — Another 
splendid  triple  group,  the  components  being,  respectively, 
65i>  83>  and  115  miles  in  diameter.  Alphonsus  contains 
a  mountain,  and  Arzachel  a  mountain  and  a  crater.  On 
the  upper"  right-hand  portion  of  the  wall  of  Alphonsus 


62  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

will  be  seen  the  fine  crater  Alpetragius,  and  at  the  lower 
part  of  Ptolemy  is  the  equally  fine  Herschel.  Above  and 
to  the  right  of  Arzachel  is  an  enormous  straight  cliff 
known  as  u  Straight  Wall "  or  Range,  and  sometimes 
called  The  Railway. 

1 6.  Pico. — An  isolated  peak  in  the  Mare  Imbrium,  8,000 
feet   high,  and  casting   an    extraordinarily  long  shadow 
under  oblique  illumination.      It  is  directly  above  Plato. 
To  its  right  and  at  about  the  same  distance  from  Plato 
is  the  curious  little  group  called  the  Teneriffe  Mountains. 

17.  COPERNICUS. — A  magnificent  ring-plain,  one  of  the 
finest,  if   not   the   finest,  in   the   moon.     It   is   56  miles 
across,  and  is  one  of  the  centres  from  which  radiate  the 
curious  light-rays  or  rills.     Below  it  is  a  pretty  pair  of 
craters,  the  larger  of  which  is  known  as  Gay-Lussac,  and, 
more  than  twice  as  far  away,  lower  and  more  to  the  right, 
is  Tobias  Mayer,  with  a  more  recently  erupted  crater  on 
its  left  side.     Between  Gay-Lussac  and  Tobias  Mayer  is 
Mount  Carpathus. 

18.  MOUNT  HUYGENS. — See  Apennines. 

19.  EUCLID. — A  small  crater  surrounded  by  a  sort  of 
nimbus.     It  is  in  an  island,  so  to  speak,  in  the  Oceanus 
Procellarum. 

20.  VITELLO. — A  most  curious  formation  at  the  upper 
end  of  the  Mare  Humorum.     It  consists  of  a  ring  enclos- 
ing another  one,  from  the  centre   of  which  rises  a  hill 
nearly   1,700   feet  high.     It  is  connected  by  a  curving 
ridge  with  the  crater  called  Doppelmayer. 

21.  THE  DORFEL  MOUNTAINS. — An  enormous  range, 
almost  on  the  limb  of  the  moon,  and  sometimes  strikingly 
seen  in  profile.     The  three  chief  peaks  probably  exceed 
26,000  feet  in  height.     Just  below  them  is  the  enormous 
ring-plain  Bailly. 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  63 

22.  WARGENTIN. — A  most  singular  object  resembling 
an  extremely  truncated  column  54  miles  across.     Webb 
compares  it  to  a  large  thin  cheese.     It  appears  to  be  a 
crater  rilled  to  the  brim  with  lava.     Just  below  it  is  the 
grand  ring- plain  Schickard,  about  153  miles  in  diameter. 

23.  AIRY. — See  28. 

24.  ERATOSTHENES. — A  splendid  crater  with  three  cen- 
tral peaks.     It  is  37^  miles  across,  and  terminates  the 
chain  of  the  Apennines. 

25.  PICCOLOMINI. — A  fine  ring-plain  57^  miles  across. 
Its  wall  is  somewhat  complex  and  has  on  its  right  edge 
a  tower  about  15,000  feet  high.     The  Altai  Mountains 
start  from  Piccolomini  and  terminate  in  Tacitus.     Their 
principal  summits  rise  to  about  13,000  feet.     Along  their 
right  side  are  the  craters  Pons  and  Fermat,  and  on  their 
left   is   Polybius,  just  above  Catherine.     The   group  of 
huge  craters-  to  the  right  of  Fermat  is  Sacrobosco. 

26.  GRIMALDI. — An   immense    dark   plain   about   148 
miles  long  by  129  wide.     It  is  probably  the  darkest  part 
of  the  moon.     Immediately  below  it  is  the  triple  group 
Lohrmann,  Hevel,  and  Cavalerius ;  to  its  right,  and  below, 
is  Riccioli ;  to  its  left,  Damoiseau,  and  above  it,  Rocca. 

27.  ARCHIMEDES. — A   fine  but   comparatively  shallow 
ring-plain  50  miles  across.     A  fine  object  in  the  rising 
or  setting  sun.     On  a  level  with  its  lowest  part  and  to 
the  left  is  Autolycus,  below  which  is  Aristillus.     These 
two    craters    are    surrounded    by   remarkable   radiating 
banks  like  lava  streams. 

28.  29,  30,  31.  WALTER,  REGIOMONTANUS,  PURBACH, 
LACAILLE. — Four  ring-plains  at  the  upper  end  of  a  curi- 
ous chain  of  craters,  of  which  the  last  but  one  is  Airy. 

32>  33>  34-  PARRY,  BONPLAND,  FRA  MAURO. — A  fine 
triple  group. 


64  THE    AMATEUR   TELESCOPIST'S   HANDBOOK. 

35.  MARE  CRISIUM. — An   immense   plain,  one   of  the 
most  conspicuous  objects  on  the  moon.     From  the  upper 
border   a   huge   cape   (Promontorium  Agarum)  projects 
about  50  miles  into  the  mare.     Just  to  the  right  of  the 
'mare  is  the  brilliant  little  crater  Proclus. 

36.  SINUS  IRIDIUM   (Bay  of    Rainbows). — A  beautiful 
formation  at  the  lower  part  of  the  Mare  Imbrium.     Beer 
and  Madler  pronounce  this  "  perhaps  the  most  magnifi- 
cent of  all  lunar  landscapes."    The  capes  at  the  right  and 
left  are  respectively  capes  Heraclides  and  Laplace. 

37.  CLAVIUS. — A  splendid  crater,  peculiarly  impressive 
in  sunrise.     It  is   more   than    142    miles   broad,  and    is 
"  encompassed  by  a  wall  damaged  by  successive  explo- 
sions,  but   still   portentously   high    and   steep,  attaining 
17,300  feet  in  one  of  its  western  peaks,  and  covering  the 
gulf  with  night  amid  surrounding  day."     (Webb.) 

38.  GASSENDI. — A  noble  crater  54  miles  across,  with  a 
group  of  conical  mountains  in  the  centre.     It  has  two 
small  craters  attached  to  its  lower  end. 

For  the  more  minute  study  of  the  above  lunar  objects 
pretty  high  powers  are  advisable.  The  illumination 
being  ample,  the  highest  powers  of  the  telescope  may  be 
profitably  employed,  if  the  atmospheric  conditions  are 
favorable  and  the  stand  steady.  But  the  most  pleasing 
views  of  the  moon  are  those  obtained  with  lower  powers, 
and  it  is  surprising  how  much  detail  may  be  observed 
with  such  powers,  if  the  objective  is  a  good  one.  I  have 
often  seen  the  streaks  extending  from  Messier,  and  the 
Valley  of  the  Alps,  with  a  power  of  48  on  a  2^-inch  glass. 

One  of  the  most  interesting  phenomena  in  connection 
with  the  moon  is  the  occultation  by  it  of  some  star  or 
planet ;  in  other  words,  the  passage  of  our  satellite  be- 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  65 

tween  a  celestial  object  and  some  point  on  the  earth's 
surface.  These  occultations  are  extremely  valuable,  as  a 
little  reflection  will  show,  in  the  determination  of  terres- 
'  trial  longitudes,  and  are  therefore  predicted  with  great 
care  and  accuracy  in  the  Nautical  Almanac.  When  a 
fixed  star  is  occulted  by  the  moon's  dark  limb,  the  sud- 
denness of  its  disappearance  is  simply  startling.  One 
instant  the  star  is  shining  in  full  brilliancy,  the  next  it  is 
as  if  blotted  out  of  existence. 

The  occultation  of  a  planet  is  a  not  unfrequent  occur- 
rence, and  is  a  spectacle  of  great  beauty  and  interest, 
although  lacking  the  "  dramatic  suddenness  "  characteris- 
tic of  the  occultation  of  a  fixed  star. 

A  singular  phenomenon  is  sometimes  witnessed  when  a 
star  is  occulted  by  the  bright  limb  of  the  moon.  This  is 
the  apparent  projection  of  the  star  on  the  edge  of  the 
moon  itself.  This  strange  appearance  has  heretofore  only 
been  noted  in  the  case  of  red  or  reddish  stars,  and  is  as 
yet  unexplained.  It  should  be  watched  for,  although  it 
is  not  very  likely  to  be  noted  in  a  small  telescope. 


CHAPTER   VIII. 

OBSERVATION,   CONTINUED. — THE    PLANETS. 

MERCURY. — It  is  a  matter  of  some  little  difficulty  to  the 
observer  whose  telescope  is  without  graduated  circles,  to 
get  a  sight  of  this  elusive  little  planet.  A  few  days  be- 
fore and  after  its  greatest  eastern  elongation  from  the 
sun  is  the  best  time  to  see  it.  At  its  western  elongation 
it  is,  of  course,  equally  easy  to  see,  provided  the  observer 
is  willing  to  get  up  a  sufficient  time  before  sunrise, 
which  few  amateurs  are  sufficiently-  enthusiastic  to  do. 
But  what  with  low-hanging  clouds  and  atmospheric  va- 
pors, the  opportunities  of  seeing  Mercury  are  rather  rare  ; 
and  moreover,  owing  to  his  nearness  to  the  sun  at  the 
best  of  times,  he  will  not  easily  be  detected  during  his 
visibility,  unless  his  place  is  known. 

Mr.  Proctor  *  gives  an  ingenious  plan  for  finding  this 
planet.  It  consists  essentially  of  calculating  the  time 
when  Mercury  will  appear  at  a  given  point,  by  taking  the 
difference  between  the  right  ascension  of  the  sun  and 
that  of  the  planet,  and  then  noting  the  time  at  which  the 
sun  crosses  the  given  point.  At  a  time  after  that,  equal 
to  the  difference  of  right  ascensions,  Mercury  will  cross 
that  point,  allowance  being  made  for  the  difference  of 
declinations.  But  by  roughly  estimating  the  position  of 
Mercury,  and  carefully  "sweeping"  about  that  point  with 
an  opera  or  field  glass,  the  planet  can  usually  be  picked 
up  without  the  employment  of  any  troublesome  devices. 

*  Half-hours,  p.  77. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  67 

The  apparent  diameter  of  Mercury  at  its  inferior  con- 
junction is  12.9",  and  at  its  greatest  elongation  only  7". 
To  examine  the  planet  with  any  satisfaction  a  high  power 
is  required — not  less  than  100  at  the  lowest. 

VENUS. — This  splendid  planet  is  one  of  the  finest  of 
celestial  objects,  but  at  the  same  time  one  of  the  most 
trying  to  the  telescope.  Its  intense  brilliancy  brings  out 
every  defect  of  the  instrument,  and  sometimes  the  ob- 
server is  compelled  to  stop  down  his  object-glass  to  obtain 
a  view  of  this  planet  free  from  u  wings."  Powers  of  from 
80  to  200  may  be  employed.  The  apparent  diameter  of 
Venus  varies  between  9.7"  in  superior  and  66.5"  in  infe- 
rior conjunction. 

An  hour  at  which  the  sun  is  still  above  the  horizon  is 
the  best  time  for  observing  Venus,  as  the  illuminated  sky 
subdues  the  glare  of  the  planet.  By  far  the  most  striking 
view  which  Venus  ever  presents  in  the  telescope  is  that 
obtained  when  she  is  in,  or  very  near,  her  inferior  con- 
junction. She  is  then  at  her  greatest  apparent  diameter  ; 
but  all  that  the  observer  can  see  is  a  brilliant  and  beauti- 
ful sickle  of  white  light.  Captain  Noble  recommends  that 
for  this  observation  the  diaphragm  between  the  lenses  of 
the  eyepiece  be  replaced  by  another  of  blackened  card- 
board, through  the  centre  of  which  has  been  pierced  a  fine 
hole  with  a  red-hot  needle. 

MARS. — For  the  satisfactory  study  of  this  most  inter- 
esting planet  an  object-glass  of  at  least  four  inches  is 
required  ;  nevertheless,  under  favorable  circumstances, 
striking  and  beautiful  views  of  Mars  may  be  obtained 
with  quite  small  apertures.  The  only  time,  however,  when 
such  telescopes  will  give  such  views  is  when  the  planet 
is  in  or  near  opposition  ;  especially  when  the  opposition 
takes  place  under  the  peculiarly  favorable  circumstances 


68  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

presented,  on  the  average,  every  fifteen  years,  when  the 
earth  is  furthest  from  the  sun  and  Mars  nearest  to  it. 
Under  such  circumstances  the  apparent  diameter  of  the 
fiery  planet  is  30.4",  which  decreases  to  4.1"  at  conjunc- 
tion. The  outlines  of  continents  and  seas  may  be  de- 
tected when  Mars  is  at  his  greatest  apparent  diameter, 
with  a  2^/2. -inch  glass  with  a  power  of  from  150  to  200, 
and  the  polar  snow-caps  may  be  seen  with  a  power  of  100 
or  even  less.  Even  a  2-inch  glass  may  do  fairly  good 
work  under  favorable  circumstances.  High  powers  are 
necessary  to  the  study  of  this  planet,  and  magnifying  may 
be  pushed  to  the  full  extent  of  the  telescope's  capacity. 

The  phases  of  Mars  may  be  seen  with  any  power  which 
will  exhibit  a  fairly  good-sized  disk.  At  quadrature  it  is 
decidedly  gibbous,  resembling  the  moon  at  about  three 
days  from  full. 

It  is  unnecessary — almost  absurdly  so — to  state  that  the 
satellites  of  Mars  are  utterly  beyond  the  reach  of  a  small 
telescope. 

THE  MINOR  PLANETS. — A  large  number  of  these  in- 
teresting little  bodies  could  be  seen  with  a  small  tele- 
scope, provided  their  places  were  known.  Tables  of  the 
elements  of  most  of  them  may  be  found  in  Kirkwood's 
Asteroids  and  in  Loomis's  Practical  Astronomy.  To  cal- 
culate the  present  position  of  any  one  of  them,  its  longi- 
tude at  a  given  epoch  is  required.  This  is  given  in  the 
case  of  each  planet  by  Loomis.  But  the  sight  of  few  of 
these  "  pocket  planets  "  will  repay  the  amateur  for  the 
laborious  computations  necessary  to  find  them  ;  so  that 
the  asteroids  may  be  regarded,  for  all  practical  purposes, 
as  outside  of  our  student's  line  of  work. 

Ceres,  at  the  most  favorable  period,  shines  as  a  seventh- 
magnitude  star  and  at  other  times  as  an  eighth.  Its  light 


THE    AMATEUR    TELESCOPIST'S   HANDBOOK.  69 

is  reddish.  Juno  is  very  similar  to  it  in  size  and  color. 
Pallas,  the  largest  of  all,  appears,  when  in  opposition,  as 
a  star  of  the  seventh  magnitude,  with  a  yellowish  tinge. 
Vesta  is  at  times  as  bright  as  a  white  sixth-magnitude 
star. 

JUPITER. — This  gigantic  orb  is  one  of  the  standard 
objects  of  study  and  admiration  for  the  amateur  telesco- 
pist.  Its  changing  belts,  its  circling  satellites,  and  the 
splendor  of  the  entire  system  render  Jupiter  a  source  of 
unfailing  pleasure  and  wonder. 

The  apparent  diameter  of  this  planet  varies  from  50.7", 
in  opposition,  to  30.8",  in  conjunction.  Very  little  optical 
aid,  therefore,  is  required  to  exhibit  its  disk.  A  power 
of  fifty  for  every  inch  of  aperture  will  exhibit  the  belts 
excellently  and  the  flattening  of  the  planet  at  the  poles. 
Lower  powers,  however,  must  be  used  to  see  the  entire 
Jovian  system  at  a  glance,  say  a  power  of  from  forty  to 
fifty  in  a  two-inch  telescope,  and  even  lower  powers  in  a 
larger  one. 

The  student  will  be  at  once  struck  with  the  singular 
and  beautiful  belts  which  stretch  across  the  planet's  disk. 
In  large  telescopes  these  belts  exhibit  striking  differ- 
ences of  color  ;  but  in  small  ones  they  are  usually  of  a 
uniform  dusky  hue.  They  change  in  number  and  breadth 
from  time  to  time,  sometimes  exhibiting  curious  and 
beautiful  scalloped  forms.  One  night's  observations  will 
reveal,  with  sufficient  powers,  a  difference  in  their  general 
aspect,  owing  to  the  swiftness  with  which  this  monster 
globe  revolves  on  its  axis. 

The  most  interesting  phenomena  in  the  Jovian  system 
are,  of  course,  those  connected  with  the  satellites.  These 
bodies  are  distinguished  by  Roman  numerals,  in  the  order 
of  their  distance  from  the  primary.  I.,  II.,  and  IV 


70  THE    AMATEUR    TELESCOPIST*S   HANDBOOK. 

appear  as  stars  of  the  seventh  magnitude  ;  III.  as  one  of 
the  sixth  magnitude.  Each  night's  observation  will  show 
them  in  a  different  position  with  reference  to  their 
primary  ;  and  it  is  interesting  to  compare  their  observed 
positions  with  the  predicted  ones  as  laid  down  for  each 
day  in  the  Nautical  Almanac.  The  tiny  fifth  satellite  is, 
of  course,  invisible  in  a  small  telescope. 

The  phenomena  connected  with  the  satellites  are  occul- 
tations,  eclipses,  and  transits.  An  occultation  is  the  pas- 
sage of  a  satellite  behind  the  planet  ;  a  transit  is  the 
passage  of  a  satellite  across  the  face  of  the  planet ;  and 
an  eclipse  is  the  entrance  of  a  satellite  into  the  shadow 
of  its  primary. 

Eclipses  may  be  observed  with  small  instruments  and 
low  powers.  Transits  are  much  more  difficult  with  such 
means.  The  shadows  of  the  satellites  on  Jupiter's  disk 
may  be  seen,  under  favorable  circumstances,  with  a  two- 
inch  glass,  but  to  see  the  satellites  themselves  projected 
on  the  disk  requires  a  larger  aperture — not  less  than 
three  inches.  The  satellites  appear  on  the  disk  as  lumin- 
ous points,  preceded  or  followed  by  their  shadows,  which 
exhibit  themselves  as  round  dark  spots,  not  black,  as  the 
visible  shadows  are  largely  composed  of  penumbra.  The 
shadow  of  IV.  is  nearly  all  penumbra,  and  even  that  of 
I.  is  not  wholly  black.*  The  shadow  of  IV.  is  nearly 
double  the  diameter  of  the  satellite  itself,  and  is  larger 
than  that  of  III.,  although  IV.  is  smaller  than  Ill.f  The 
shadow  precedes  the  satellite  when  Jupiter  is  passing  from 
conjunction  to  opposition,  but  follows  it  when  the  planet 
is  between  opposition  and  conjunction. 

The   occultations  are  the   most  difficult  of  the  Jovian 

*  Proctor,  Half-hours,  pp.  86,  87.  f  Lassell. 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK.  71 

phenomena  to  small  apertures  ;  but  it  may  be  added 
that  they  are  also  the  least  interesting.  All  these  phe- 
nomena are  duly  predicted  in  the  Nautical  Almanac. 

SATURN. — Beyond  all  comparison  this  wonderful  planet 
is  the  most  beautiful  and  striking  object  in  the  solar  sys- 
tem. Its  retinue  of  satellites  and  its  stupendous  rings 
make  it  by  far  the  most  gorgeously  attended  of  all  the 
planets.  Its  satisfactory  study  is  just  beyond  the  powers 
of  a  small  telescope,  an  aperture  of  four  inches  being 
required  for  a  reasonably  complete  view.  Enough  may 
be  seen  with  a  small  instrument,  however,  to  make  Saturn 
a  source  of  unfailing  wonder  and  admiration.  The  ap- 
parent diameter  of  this  planet  varies  from  14.6",  in  con- 
junction, to  20.3",  in  opposition. 

The  belts  of  Saturn  are  much  less  conspicuous  than 
those  of  Jupiter,  but  a  three-inch  telescope,  or  even,  at 
times,  a  two-inch,  will  show  them.  The  satellites  will 
prove  very  difficult  objects  to  our  observer,  with  the 
exception  of  Titan  and,  under  some  circumstances, 
Japetus.  A  two-inch  glass  will  show  these,  if  Japetus 
is  near  its  western  elongation  ;  a  three-inch  may  show 
Rhea  also ;  a  four-inch  will  add  Tethys  and  Dione. 
The  others  require  large  and  powerful  instruments. 
Eclipses,  etc.,  in  the  Saturnian  system  need  not  here  be 
dwelt  upon,  as  they  will  be  utterly  beyond  our  observer's 
telescope. 

The  ring  may  be  seen  readily  with  a  two-inch  tele- 
scope. According  to  Mr.  Proctor,*  this  aperture  will 
also  show  Ball's  (Cassini's)  division  in  the  ring,  but  I 
have  never  been  able  to  detect  this  feature  with  any- 
thing under  three  inches.  Nothing  below  four  inches  will 

*  Half -hours,  p.  92. 


72  THE    AMATEUR    TELESCOPIST's    HANDBOOK. 

show  the  curious  and  beautiful  inner  dusky  or  "  crape  " 
ring. 

The  rings  are  known  as  A,  B,  and  C,  counting  from 
the  outer  ring.  Ball's  division  forms  the  boundary 
between  A  and  B,  but  A  is  also  marked  by  Encke's 
division,  which  is  much  beyond  the  powers  of  a  small 
telescope. 

A  three-inch  glass  should  show  the  difference  between 
the  colors  of  rings  A  and  B,  the  latter  being  decidedly 
more  silvery  than  the  former  and  presenting  a  lovely  con- 
trast with  the  yellow  ball  of  the  planet. 

High  powers  may  be  used  upon  Saturn  with  more  satis- 
faction than  upon  Jupiter,  and  the  observer  is  advised  to 
try  upon  this  glorious  orb  the  highest  powers  that  his  tele- 
scope will  bear.  He  will  find  it  worth  his  while  to  watch 
and  wait  for  atmospheric  conditions  sufficiently  favorable 
for  this  purpose. 

URANUS  AND  NEPTUNE. — Our  amateur  will  be  able  to 
see  these  planets  as  stars,  and  even,  with  sufficient  power, 
to  raise  them  to  disks.  To  find  them  with  an  altazimuth, 
their  right  ascension  and  declination  must  be  taken  from 
the  Nautical  Almanac,  and  their  places  carefully  marked 
on  a  map  or  planisphere.  They  may  then  be  aligned  from 
neighboring  stars.  The  apparent  diameter  of  Uranus 
never  reaches  four  seconds,  and  a  power  of  at  least  two 
hundred  is  required  to  show  it  as  a  disk.  Neptune  will 
hardly  be  distinguished  from  a  dull  eighth-magnitude 
star  except  by  the  greater  steadiness  of  its  light  and 
the  absence  of  diffraction  rings  around  it.  •  "  What  is 
the  lowest  power,"  says  Mr.  Proctor,  "which  will  ex- 
hibit Neptune  as  a  disk,  I  do  not  know  ;  but  I  am  certain 
no  observer  can  mistake  him  for  a  fixed  star  with  a  two- 
inch  aperture  and  a  few  minutes'  patient  scrutiny  in 


THE    AMATEUR    TELESCOPIST'S   HANDBOOK.  73 

favorable  weather."*  "The  observer  with  a  three-inch 
telescope,"  says  Captain  Noble,  "  may  be  contented  if  he 
can  fairly  satisfy  himself  that  it  is  not  a  star  that  he  is 
looking  at."f 

*  Half-hours,  p.  92.  \  Three-inch  Telescope,  p.  80. 


CHAPTER   IX. 

PRICES   OF    TELESCOPES    AND    THEIR    ACCESSORIES. 

FOR  the  convenience  of  intending  purchasers  of  tele- 
scopes, I  deem  it  essential  to  the  completeness  of  this 
little  handbook  to  give  the  names  of  certain  well-known 
and  reliable  opticians  and  manufacturers,  together  with 
the  prices  asked  by  them  for  their  instruments.  I  sub- 
join extracts  from  the  price-lists  of  three  American  and 
two  English  artists  and  dealers,  by  the  aid  of  which  the 
amateur  may  lay  out  the  sum  set  apart  for  his  astronomi- 
cal recreations  to  the  best  advantage.  The  firms  referred 
to  are  the  following  : 

ALVAN  CLARK  &  SONS,  CAMBRIDGEPORT,  MASS. — These 
world-renowned  artists  are  the  makers  of  the  great  Lick 
telescope  of  thirty-six  inches  aperture  ;  of  the  Pulkowa, 
thirty-inch  ;  the  Washington,  twenty-six-inch  ;  the  Univer- 
sity of  Virginia,  twenty-six-inch  ;  and  other  famous  and 
magnificent  instruments.  They  make  for  the  use  par- 
ticularly of  amateurs  a  series  of  comparatively  small  and 
simply  mounted  refractors  of  low  price  and,  of  course, 
distinguished  excellence. 

GEO.  N.  SAEGMULLER,  late  FAUTH  &  Co.,  WASHING- 
TON, D.  C. — This  eminent  firm  are  the  makers  of  the 
twelve-inch  equatorials  of  the  Ladd  Observatory,  Provi- 
dence, R.  I.,  the  Georgetown  College  Observatory,  and 
the  new  Naval  Observatory  at  Washington  ;  and  of  the 
nine-inch  equatorial  of  the  Catholic  University  in  the 
same  city. 


THE   AMATEUR   TELESCOPIST*S   HANDBOOK. 


75 


QUEEN  &  Co.,  PHILADELPHIA. — This  firm  manufactures 
and  imports  a  cheaper  but  well-recommended  class  of 
instruments. 

J.  COOKE  &  SONS,  YORK,  ENGLAND. — These  celebrated 
artists  are  the  makers  of  the  noble  twenty-five-inch  New- 
all  refractor  now  at  Cambridge,  and  other  grand  tele- 
scopes. They  rank  among  the  great  opticians  of  the 
world. 

HORNE,  THORNTHWAITE  &  WOOD,  416  STRAND  AND 
74  CHEAPSIDE,  LONDON. — An  old  and  well-known  firm, 
making  a  cheaper  class  of  telescopes. 

ACHROMATIC  OBJECT-GLASSES,  MOUNTED  IN  CELLS. 


CLARK— 

3-inch. 

Si-inch. 

4-inch. 

4|-inch. 

5-inch. 

6-inch. 

$50.00 

$75-00 

$IOO.OO 

$140.00 

$200.00 

$35°-00 

SAEGMULLER  — 

2-inch. 

3-inch. 

3^-inch. 

4-inch. 

4!  inch. 

5-inch. 

$30.00 

$6o.OO 

$8o.OO 

$IOO.OO 

$140.00 

$l8o.OO 

5|-inch. 

6-inch. 

$250.00 

$360.00 

QUEEN  — 

2^-inch. 

2|-inch. 

3  -inch. 

Sl'inch. 

4-inch. 

4i-inch. 

$15-00 

$25.00 

$30.00 

$55-0° 

$80.00 

$125.00 

5-inch. 

5l-inch. 

$265.00 

$350-00 

COOKE— 

2-inch. 

2^-inch. 

2^-inch. 

2|-inch. 

3-inch. 

3i-inch. 

£2  2S- 

£3  5s- 

£4  *5S 

.     £1 

£9  iw. 

£*4 

4-inch. 

4^-inch. 

5  -inch. 

6-inch. 

£34    £48 

HORNED  THORNTHWAITE  &  WOOD — 

2^-inch.  3-inch.          3^-inch.         4^-inch.          5-inch. 


76  THE   AMATEUR    TELESCOPIST's   HANDBOOK. 


TELESCOPES,  UNMOUNTED. 

CLARK. — Each  telescope  is  provided  with  a  finder, 
diagonal  eye-tube,  front-surface  reflecting  solar  prism, 
one  terrestrial  eye-piece,  and  four  celestial  eye-pieces. 

4-inch.      4|-inch.      5-inch.      6-inch. 
$220.00     $270.00     $360.00     $550.00 

The  same  without  any  accessories  except  four  celestial 
eye-pieces : 

4-inch.      4^-inch.      5-inch.       6-inch. 
$l6o.OO     $2IO.OO     $300.00     $490.00 

SAEGMULLER. — Telescopes  of  3  inches  and  upward 
have  finders.  The  figures  in  parentheses  refer  to  the 
number  of  eye-pieces  furnished  with  each  instrument. 

2|-inch(2).    3 -inch  (3).    3|-inch  (3).   4-inch  (4).  4^-inch  (4).  5-inch  (5). 
$90.00      $145.00      $165.00      $2IO.OO     $265.00    $325.00 

QUEEN. — These  instruments  have  blackened  steel  bodies 
with  brass  mountings.  Sizes  below  4  inches  are  without 
finders.  The  3-inch  telescope  is  provided  with  three 
eye-pieces,  all  others  with  four. 

3-inch.    3|-inch.    4-inch.    4^-inch.    5-inch.   6-inch. 
$125.00  $175.00  $225.00  $300.00  $450.00  $600.00 

COOKE. — These  telescopes  have  brass  tubes,  and  all 
over  2^  inches  aperture  are  provided  with  finders,  dew- 
caps,  and  solar  eye-pieces.  Each  has  one  terrestrial  eye- 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  77 

piece.     The  figures  in  parentheses  refer  to  the  number  of 
astronomical  eye-pieces  furnished  with  each  instrument. 

2i-in.  (i).    2|-in.  (2).    2f-in.  (2).  3-in.  (3).    3^-in.  (4).     4-in.  (4). 

£10  i$s.     £14      £iS  los.  £23 

4i-m.  (4).  5  -in.  (5). 
£54 


PORTABLE  EQUATORIAL  STANDS. 

CLARK.  —  Plain  equatorial  of  best  construction,  without 
circles,  with  tangent  wheel  for  slow  motion  in  right  as- 
cension, $110. 

SAEGMULLER.  —  Equatorial  stand  with  tangent  move- 
ments, silvered  circles  reading  respectively  to  5  seconds 
of  R.  A.  and  single  minutes  of  declination,  $150. 

QUEEN.  —  Small  equatorial  head,  without  stand,  $18. 
Universal  Equatorial  (i.e.,  one  adaptable  for  any  latitude), 
of  fine  quality,  without  circles,  fitted  with  tangent  move- 
ment, brass-mounted,  $75  ;  clamp  for  telescope,  $6  extra  ; 
universal  handle  for  R.  A.  wheel,  $5  extra.  A  larger  and 
finer  stand,  with  graduated  adjustment  for  latitude  ; 
7-inch  circles  divided  on  solid  silver,  reading  to  4  seconds 
in  R.  A.  and  i'  in  declination  ;  circles  read  by  verniers 
and  microscopes  ;  $250. 

COOKE.  —  Fine  and  heavy  equatorial  tripod-stand,  uni- 
versal adjustment,  circles  graduated  on  silver,  with  ver- 
niers and  reading  microscopes  ;  tangent  screw  motions 
in  R.  A.  and  declination  brought  down  to  eye-end,  and 
cross-levels.  Made  in  three  sizes. 


Complete,  for  telescopes  5  to  5^  inches  ... 

4  to  4}^      "        ....      50 
«  "  "          3  to  3^      "        ....      4i 


78  THE    AMATEUR    TELESCOPIST's    HANDBOOK. 

With  gun-metal  circles  instead  of  silver,  the  prices  of 
the  above  stands  are  ,£62  ios.,  £47,  and  £$&  ios.,  re- 
spectively ;  and  if  the  tangent-motion  is  not  to  be  brought 
down  to  the  eye-end  (a  luxury  which  may  be  dispensed 
with)  deduct  ^8,  ^7,  and  £6  ios.  from  the  foregoing 
prices. 

H.,  T.  &  W. — Universal  equatorial  for  telescopes  up  to 
three  and  a  half  feet  long,  6-inch  brass  circles  reading 
respectively  to  ios.  in  R.  A.  and  3'  in  Dec.,  ^15  i$s. 
Same,  without  stand,  for  a  3  J^-inch  telescope,  with  silver 
circles  and  tangent  movement,  £$o  ;  for  4^ -inch  tele- 
scope, £60. 

TELESCOPES  COMPLETE. 

CLARK. — Mounted  on  superior  equatorial  stand,  with- 
out circles,  finished  in  first-class  style,  each  telescope 
provided  with  a  finder,  diagonal  eye-tube,  front-surface 
reflecting  solar  prism,  one  terrestrial  and  four  celestial 
eye-pieces. 

4-inch.      4^-inch.     5-inch.      6-inch. 
$325.00    $380.00    $450.00    $650.00 

SAEGMULLER. — May  be  ascertained  from  foregoing 
estimates. 

QUEEN. — May  be  ascertained  from  foregoing  estimates. 

COOKE. — If  equatorially  mounted,  the  prices  may  be 
estimated  from  data  already  given  ;  but  if  mounted  on 
altazimuth  stand,  the  prices  are  as  follows  : 

2^-inch,  £\6  i6s.  ;  2>^-inch,  ^£20  ;  2^-inch,  ^28,  or 
with  tangent  screws,  £$2  ;  3-inch,  ^32,  with  t.  s.,  £36  ; 
3% -inch,  ^39,  with  t.  s.,  ^43  ios.  ;  3^-inch,  ^42  jos., 
with  t.  s.,  ^47  ;  3^-inch,  ^50  IQS.,  with  t.  s.,  ^55  ios.  ; 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  79 

4-inch,  ^55  ios.,  with  t.  s.,  ^60  los.  ;  4^-inch,  £62  ios., 
with  t.  s.,  ^67  105.  ;  4^  -inch,  ^"69,  with  t.  s.,  ^76  IO.T.  ; 
5-inch,  ^84,  with  t.  s.,  ^94. 

H.,  T.  &  W.  —  These  telescopes  have  brass  bodies.  Each 
is  provided  with  a  finder  and  one  terrestrial  eye-piece 
and  is  mounted  on  a  brass  pillar-and-claw  stand.  The 
figures  in  parentheses  refer  to  the  number  of  celestial  eye- 
pieces furnished  with  each  instrument. 
3-in.  (i).  3i-in.  (2).  3^-in.  (3).  3f-in.  (4).  4-in.  (5).  4Hn.  ($). 
i4s.  £iS  iSs.  £35  ^45  ^55 


Mounted  on  equatorial  stands  with  diagonal  eye-tube, 
solar  eye-piece,  circles,  levels,  etc. 

3^-inch.  4-inch.  4^-inch.  5-inch. 

^80  ^95 


With  the  last  two  instruments  an  iron  pillar  is  fur- 
nished, if  desired,  in  lieu  of  the  tripod,  without  extra 
charge. 

EYE-PIECES  (HUYGENIAN). 

SAEGMULLER.  —  From  J-inch  to  i-inch,  $5.50. 

QUEEN.  —  From  -J-inch  to  i-inch,  $5.50.  Munich  3-lens 
eye-pieces,  giving  extra  large  field,  i-inch,  $6.00  ;  J-inch 
to  -£-inch,  $4.50.  Adapter  to  fit  draw-tube,  $1.50. 

COOKE.  —  195-.  each. 

H.,  T.  &  W.—  From  155.  to^i  55. 

ACCESSORIES. 

First-surface  reflecting  prism  for  solar  observations  : 
Saegmuller,  $i  ;  Cooke,^i  5*.;  H.,  T.  &  W.,  £i  125. 


8o  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 


CHEAPER  TELESCOPES. 

The  cheapest  of  the  above-described  instruments  will 
doubtless  be  beyond  the  means  of  many  a  student  to 
whom  the  possession  of  a  telescope  is  an  object  of  ear- 
nest desire.  But  they  are  all  instruments  of  a  high 
class,  some  of  them,  indeed,  of  the  most  perfect  quality 
that  art  can  produce.  While  such  telescopes  are  of  the 
kind  which  the  amateur  should  strive  to  secure,  there  are 
others  to  be  had  of  very  fair  quality  and  much  lower 
price.  A  three-inch  telescope  of  French  manufacture, 
fitted  with  a  terrestrial  eye-piece  magnifying  fifty  times, 
and  a  celestial  one  magnifying  one  hundred  times,  is 
commonly  sold,  unmounted,  by  city  opticians  for  |6o, 
and  will  do  very  fair  service  if  provided  with  one  or  two 
additional  eye -pieces.  A  better  instrument  of  the  same 
aperture,  made  by  Bardou,  of  Paris,  and  mounted  on  a 
pillar-and-claw  stand,  is  sold  for  $120. 

But  should  even  the  cheaper  of  these  instruments  be 
beyond  the  means  of  the  student,  let  him  not  despair.  A 
good  second-hand  "spy-glass"  may  often  be  purchased 
for  a  small  sum  ;  and  if  its  aperture  equal  two  inches,  as 
that  of  many  ship-telescopes  does,  it  may  be  mounted 
after  one  of  the  methods  described  in  Chapter  II.  and 
provided  with  either  astronomical  eye-pieces,  or,  what 
serves  just  as  well  for  small  apertures,  with  microscopic 
eye-pieces.  These  are  of  the  Huygenian  form,  and  cost 
less  than  the  others.  Such  eye-pieces,  of  the  best  quality, 
may  be  obtained  from  the  Bausch  and  Lomb  Optical  Co., 
of  Rochester,  N.  Y.,  for  $3  each. 

Such  a  telescope  was  used  by  the  author  for  many 
years ;  and  if  the  objective  is  at  all  good,  quite  a  large 


THE   AMATEUR    TELESCOPIST  S    HANDBOOK. 


8l 


proportion  of  the  objects  described  in  this  book  will  be 
found  to  be  within  the  range  of  its  powers. 

The  catalogues  and  circulars  of  the  following  artists 
and  manufacturers  may  also  be  consulted  with  profit : 

John  Byrne,  with  Gall  &  Lembke,  21  Union  Square, 
New  York  ;  a  maker  of  objectives,  etc.,  of  the  highest 
class. 

J.  A.  Brashear,  Allegheny,  Pa.  Highest-grade  objec- 
tives, etc. 

Warner  &  Swasey,  Cleveland,  Ohio.  Equatorial  mount- 
ings of  the  finest  character. 

-  W.   &   D.  Mogey,  Bayonne,   N.   J.     Small   equatorial 
mountings. 


THE  GREEK  ALPHABET. 

a  Alpha.  z    Iota. 

§  Beta.  K  Kappa. 

y  Gamma.  A  Lambda. 

d  Delta.  p.  Mu. 

£   Epsilon.  v  Nu. 

2  Zeta.  %  Xi. 

77  Eta.  o  Omicron. 

6  Theta.  n  Pi. 


p  Rho. 
a  Sigma. 
r  Tau. 
v  Upsilon. 
cp  Phi. 
X  Chi. 
$  Psi. 
co  Omega. 


(JMesttal 


In  the  following  catalogue  the  positions  of  objects  are 
given  for  the  year  1890,  except  in  a  few  cases  where  the 
positions  are  for  1880,  and  are  stated  to  be  so.  I  have 
not  considered  it  necessary  to  bring  these  latter  positions 
up  to  date,  as  they  are  sufficiently  accurate  for  finding 
purposes. 

Position  angles  are  omitted,  as  they  serve  no  purpose 
for  the  amateur  telescopist. 

All  quotations  not  otherwise  credited  are  from  Admiral 
Smyth's  Cycle  of  Celestial  Objects,  which  is  the  principal 
source  from  which  these  lists  have  been  compiled. 

Greek  letters  not  followed  by  the  name  of  a  constellation 
refer  to  stars  in  the  constellation  then  under  description. 

The  following  abbreviations  are  employed  in  this  cata- 
logue : 

R.  A.,  Right  Ascension. 

Dec.,  Declination  ;  +,  North  ;  —  ,  South. 

D.,  Distance. 

1$,  Sir  William  Herschel.  The  Roman  numerals  fol- 
lowing this  sign  refer  to  the  number  of  that  catalogue  of 
nebulae  containing  the  object  under  description. 

H.,  Sir  John  Herschel's  General  Catalogue  of  Nebulae, 
1864. 

M.,  Messier's  Catalogue  of  103  Nebulae,  1783-84. 

P.,   Piazzi's   Palermo   Catalogue,  1814.      The  Roman 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 


numerals  following  this  initial  refer  to  that  one  of  the 
XXIV.  hours  of  R.  A.  into  which  this  catalogue  is  di- 
vided, which  contains  the  object  under  description. 

h.,  Sir  John  Herschel's  First  Catalogue  of  Nebulae,  1833. 

h.*,  Sir  John  Herschel's  General  Catalogue  (so-called) 
of  Double  Stars. 

B.,  Bode's  Catalogue. 

Lai.,  Lalande's  Catalogue. 

2,  Wilhelm  Struve's  great  Dorpat  Catalogue  of  Double 
Stars. 

B.  A.  C.,  British  Association's  Catalogue. 

Birm.,  Birmingham's  Catalogue  of  Red  Stars,  1877. 

Dunlop,  His  Catalogue  of 
Southern  Clusters  and  Nebulae. 

A  telescopic  field  is  divided 
into  four  imaginary  quadrants, 
which  are  designated  respect- 
ively south  preceding,  south  fol- 
lowing, north  preceding,  and 
north  following ;  usually  ex- 
pressed by  the  initials  sp,  sf, 
etc.  They  are  placed  as  in  the 
diagram. 

The  number  of  stars  in  each  constellation  is  given 
according  to  Bode's  estimate. 

ALIGNMENT    STARS. 

The  position,  with  reference  to  conspicuous  stars,  of 
many  of  the  objects  used  in  the  following  pages  for  the 
"  alignment,"  to  use  Admiral  Smyth's  convenient  word,  of 
inconspicuous  celestial  bodies,  is  already  given  in  the 
Catalogue  itself  ;  but  I  append  directions  for  quickly  and 


84  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

easily  finding  all  the  stars  used  for  alignment  in  these 
lists  in  order  to  save  the  student  from  having  to  distract 
his  attention  and  unfit  his  eyes  for  immediate  use  at  the 
telescope  by  poring  over  a  map  by  lantern  light. 

While  it  is  by  no  means  necessary,  the  observer  will 
greatly  facilitate  his  work,  increase  his  knowledge  of  the 
heavens,  and  keep  his  eyes  in  good  condition  for  the  tele- 
scope by  memorizing  the  positions  of  all  these  guiding 
stars — a  task  which  will  be  found  far  less  formidable 
than  it  sounds. 

A  knowledge  of  all  first-magnitude  stars,  of  Polaris,  and 
of  the  general  positions  of  the  constellations  is  assumed. 

ANDROMEDA. — Draw  a  line  from  Polaris  through  the 
brighter  of  the  two  stars  forming  the  seat  of  Cassiopeia's 
Chair,  and  extend  it  25°.  It  will  reach  a  point  3°  W.  of 
a  second-mag,  star,  which  is  ft.  S.W.  of  /?,  and  y-J0  from 
it,  is  a  third-mag.,  which  is  6,  and  the  same  distance  from 
d,  W.  and  a  little  S.,  is  a  second-mag.,  which  is  a.  3-^° 
N.W.  of  /?,  and  forming  with  it  a  curved  line,  are  two 
fourth-mag,  stars,  the  lower  of  which  is  //,  the  other  v. 

AQUARIUS. — Draw  a  line  due  N.  from  Fomalhaut  14°. 
It  will  pass  very  near  6,  of  mag.  three,  the  brightest  star 
in  that  neighborhood.  Draw  a  line  from  Fomalhaut 
through  d,  and  16°  on.  3^  W.  of  the  point  thus  reached 
are  three  stars  forming  a  nearly  straight  line  7°  long,  due 
E.  and  W.  They  are,  in  that  order,  77  (4),  £  (3),  and  a  (3). 
Just  S.  of  the  middle  of  the  line  is  y  (3).  10°  S.W.  of  a 
is  ft  (3).  A  line  from  Fomalhaut  to  tf,  and  8J°  on,  reaches 
A  (4),  and  6°  E.,  about  2°  S.,  is  a  little  group  of  three  stars, 
of  which  the  fourth-mag,  one  is  ^.  8°  exactly  S.W.  of 
ft  is  v  (4). 

AQUILA. — a  is  almost  midway  between  y  (3)  and/?  (4), 
the  three  stars  forming  a  line  nearly  5°  long  with  ft  at  the 


THE    AMATEUR    TELESCOPIST'S   HANDBOOK.  85 

S.  end.  This  line  points  to  6  (3),  8|°  S.  Just  east  of 
the  line  between  a  and  /?,  i°  from  #,  is  £  (5).  4^°  W.  of 
a,  nearly  at  right  angles  with  the  above  line,  is  ju  (5).  A 
line  from  £  to  j3  and  4^°  on  passes  about  i°  E.  of  ?;. 
Draw  a  line  from  Polaris  through  Lyra,  and  at  a  point 
1 2^°  N.W.  of  Altair  it  will  strike  a  third-mag,  star,  which 
is  %  (3).  i8|°  due  S.  of  £  is  A.  (3).  2°  N.W.  of  %  is  *  (4). 

ARIES. — This  constellation  contains  but  two  stars  of 
mag.  three,  a  is  24°  due  W.  of  the  Pleiades,  and  /3  4° 
S.W.  of  a.  y  (4)  is  Ji°  S.  of  ft.  s  (4)  is  I2-J-0  from  a,  on 
line  to  Aldebaran. 

AURIGA.— ft  (2)  is  7^°  E.  of  a.  9°  due  N.  of  ft  is  d 
(4).  5-j-0  S.  and  somewhat  W.  from  #,  are  two  fourth- 
mag,  stars  about  i°  apart.  The  one  to  the  E.  is  77,  the 
other  £. 

BOOTES. — The  first  bright  star  N.E.  of  a  is  e,  10°  dis- 
tant, and  8£°  further  on  in  the  same  line  is  d  (3).  ft  (3) 
is  8°  N.,  a  little  W.  from  tf. 

CANCER. — Draw  a  line  from  Regulus  to  Procyon.  It 
will  pass,  at  a  distance  of  17^°  from  the  former — something 
less  than  half  way — 3°  S.  of  a  fourth-mag,  star,  which  is  a. 
6|°  N.  and  3^°  W.  of  a  is  a  fourth-mag.,  which  is  6.  11° 
due  N.  of  6  is  i  (4). 

CANES  VENATICI. — A  line  from  Polaris  through  the 
northernmost  of  the  three  stars  forming  the  handle  of  the 
"Dipper,"  and  17^°  on,  will  reach  a,  a  bright  third-mag, 
star. 

CANIS  MAJOR. — The  conspicuous  third  mag.  5f°  W. 
and  somewhat  S.  of  Sirius  is  ft.  S.  and  W.  of  a  are  four 
third-mag,  stars  forming,  as  it  were,  three  arms  of  a  cross. 
The  central  one  is  6,  the  furthest  W.  is  e,  the  furthest  E., 
77.  A  line  from  r)  to  e  and  9°  on  reaches  a  point  i-J°  S. 
of  $  (3).  5°  N.  and  2°  W.  of  a  is  6  (4). 


86  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

CANIS  MINOR. — fi  is  the  third-mag,  star  4^°  N.W. 
of  a. 

CAPRICORNUS. — Draw  a  line  from  Fomalhaut  through 
e  Pise.  Aust.,  the  fourth-mag,  star,  5^°  N.W.  of  it,  and  17!° 
on.  It  will  reach  a  fourth-mag,  star,  the  easternmost  of 
three  such  stars,  which  form  a  straight  line  from  E.  to 
W.  8|°  long.  They  are,  in  that  order,  y,  i,  and  6.  /3  is 
the  third-mag,  star  about  i-J°  E.,  a  little  N.  of  y.  The 
fourth-mag,  star  5^°  S.,  a  little  E.  from  z,  is  £.  A  line 
from  i  to  6  and  11°  on  will  reach  a  point  3^°  S.  of  a  third- 
mag,  star,  which  is  /?,  and  2^°  N.  of  ft  is  a. 

CASSIOPEIA. — The  well-known  "  Chair  "  is  composed  as 
follows  :  Dividing  its  six  stars  into  feet,  seat,  and  back, 
we  find  that  the  feet  are  a  (South)  and  /3  (North)  ;  the 
seat,  y  (S.)  and  n  (N.)  ;  the  back,  6  (S.)  and  e  (N.). 
£  and  0  are  two  fourth-mag,  stars,  which  form  a  scalene 
triangle  with  a;  8  being  4°  S.E.  of  a,  and  2  3°  S. 
of  a. 

CEPHEUS. — This  constellation  is  marked  by  an  irregular 
square  of  four  third-magnitude  stars,  the  longest  diagonal 
of  which  square  is  about  12°.  On  the  W.  side  of  the 
square  the  star  nearest  the  pole  is  ft,  the  other  a.  On 
the  E.  side  the  star  nearest  the  pole  is  z,  the  other  £. 
1 1|°  N.E.  of  ft  is  y  (3).  2i°  due  E.  of  2  is  d  (4).  4°  W., 
a  trifle  S.  from  a,  is  rj  (4). 

CETUS.— 26°  S.W.  of  Aldebaran  is  a  (3).  5°  W.,  a 
little  S.  from  a,  is  y  (3).  8^°  exactly  S.W.  from  y  is  o. 
A  line  from  y  to  o,  and  10°  on,  reaches  £  (3).  io-j-°  due 
W.  from  8,  is  77  (3).  2°  N.  of  a  line  from  2  to  77  is  6  (3). 
10°  S.W.  of  rf  is  ytf  (3).  IT°  N.W.  of  £  is  z  (3).  The 
alignments  here  sound  difficult,  but  they  are  in  reality 
very  easy,  as  the  constellation  contains  so  few  conspicu- 
ous stars. 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  87 

CORONA  BOREALIS. — 18°  due  W.  and  7^°  N.  from 
Arcturus — 20°  from  it — is  a  second-mag,  star,  which  is  a. 
Two  fourth-mag,  stars  lie  just  E.  of  it,  forming  with  it  a 
line  3|°  long.  The  nearest  to  a  is  y,  the  other  6. 

CORVUS. — A  line  drawn  S.W.  from  Spica  17}°  will 
reach  the  centre  of  the  square  of  third-mag,  stars  mark- 
ing Corvus.  The  western  stars  of  the  square  are  y  (N.) 
and  s  (S.)  ;  the  eastern,  d  (N.)  and  ft  (S.). 

CRATER. — This  asterism  adjoins  Corvus  on  the  W.  It 
contains  one  third-mag,  star,  which  is  d ;  6°  S.W.  of  d  is 

«(4). 

CYGNUS. — The  cross  in  this  constellation  is  made  up  as 
follows  :  In  the  centre  is  y  ;  furthest  N.,  a  ;  furthest 
S.,  ft.  In  the  cross-piece  :  furthest  E.,  £ ;  furthest  W.,  6. 
6£°  S.E.  of  s  is  Z  (3).  5°  N.  of  Z,  is  v  (4).  About 
8°  N.,  somewhat  W.  of  d,  are  two  fourth-mag,  stars  nearly 
3°  apart.  The  nearest  to  d  is  z,  the  other  H.  A  line 
from  8,  to  v,  and  iij°  on,  will  reach  p  (4). 

DRACO. — Draw  a  line  from  Polaris  to  Wega;  22^°  from 
the  former  the  line  will  pass  3°  W.  of  a  third-mag,  star, 
which  is  d.  17^°  S.W.  of  6  will  be  seen  a  trapezium  com- 
posed of  two  third-mag.,  one  fourth-mag.,  and  one  second- 
mag,  stars.  The  eastern  of  these  are  £  (N.)  and  y  (S.)  ; 
the  western,  v  (N.)  and  /3  (S.).  y  and  v  point  to  a  third- 
mag,  star  nj°  N.W.,  which  is  rj. 

ERIDANUS. — 1£°  W.,  a  little  S.  from  Rigel,  is  a  fourth- 
mag,  star,  which  is  A.  3|-0  almost  due  N.  of  A  is  ft  (3).  A 
line  from  the  middle  of  Orion's  belt  through  /?,  and  19°  on, 
reaches  y  (3).  The  two  third-mag,  stars  N.W.  of  y  are 
d  (E.)  and  f  (W.);  and  9°  nearly  due  W.  of  e  is  77. 

GEMINI.— 8°  S.W.  of  Pollux  is  d  (3).  12°  from  <S  on 
line  to  Betelgeuse  is  y  (3).  7^°  N.W.  of  y  will  be  seen 
two  third-mag,  stars,  which  are  //  (E.)  and  r\  (W.).  4° 


88  THE   AMATEUR    TELESCOPIST's    HANDBOOK. 

S.E.  of  y  is  £  (4).  12°  due  N.  of  £  is  £  (3).  4°  W.,  a 
little  S.  from  <?,  is  3  (4). 

HERCULES. — A  line  from  Wega  drawn  W.  and  a  little 
S.  20°  will  reach  the  centre  of  a  large  trapezium  of  four 
third-mag,  stars.  Of  these  the  eastern  members  are 
n  (N.)  and  e  (S.)  ;  the  western,  ??  (N.)  and  <§  (S.).  nj° 
due  S.  of  TT  is  tf  (3),  and  the  same  distance  due  S.  of  $ 
is  a.  n  and  f,  and  also  77  and  £,  point  to  a  spot  2°  E.  of 
ft  (2).  3°S.W.  of/»isy(3). 

HYDRA. — About  13°  E.,  a  trifle  N.  from  Procyon,  are 
two  third-mag,  stars  2j°  apart.  They  are  8,  (E.)  and 
s  (W.).  17°  S.E.  of  these  is  a  (2).  On  the  W.  border  of 
Crater  is  a  third-mag,  star,  which  is  v,  and  5^°  nearly  due 
E.  of  v  is  yw  (4).  7  is  the  fourth-mag,  star,  12°  S.,  a  trifle 
W.  from  Spica. 

LEPUS. — This  asterism  is  S.  of  Orion.  It  contains  only 
two  third-mag,  stars,  which  are  a  (N.)  and  ft  (S.). 

LEO. — The  six  stars  forming  the  Sickle,  counting  from 
Regulus,  are  a,  77,  y,  £,  ju,  and  e.  /3  (2)  is  25°  E.,  a  little 
N.  from  ex.  £  is  a  fifth-mag,  star  9°  nearly  due  W.  of  a. 

LIBRA. — A  line  drawn  27°  due  E.  from  Spica  reaches  a 
point  2°  S.  of  a  third-mag,  star,  which  is  ft.  91°  exactly 
S.W.  from  ft  is  a  (3). 

LYRA. — S.  and  somewhat  E.  from  a  about  6|°  are  two 
third-mag,  stars  2°  apart.  They  are  y  (E.)  and  ft  (W.). 
7°  due  E.  of  a  are  two  fourth-mag,  stars  less  than  2°  apart. 
They  are  77  (N.)  and  0  (S.). 

OPHIUCUS. — 16°  N.,  a  trifle  E.  from  Antares,  is  £  (3)  ; 
and  N.E.  of  Antares  about  14°  is  77  (3).  9^°  S.  and  2^-° 
E.  from  77  is  0  (4).  «  is  the  second-mag,  star  furthest  N. 
in  the  constellation.  8^°  S.,  a  little  E.  from  a,  is  ft  (3). 
x  (3)  *s  9J-  E-  and  considerably  S.  from  #,  forming  with 
it  and  ft  a  scalene  triangle,  y  (4)  is  2°  S.E.  from  /?. 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  89 

ORION. — y  (2)  is  at  the  N.W.  corner  of  the  great 
quadrilateral,  and  n  (3)  at  the  S.E.  The  stars  in  the 
belt,  from  W.  to  E.,  are  6,  e,  and  £.  The  fourth-mag. 
3°  from  tf,  almost  on  the  line  to  Rigel,  is  77 ;  and  the 
northernmost  of  the  three  stars  in  the  head  is  A. 

PEGASUS. — A  line  from  Altair  E.,  a  trifle  N.,  28°  will 
reach  a  second-mag,  star,  which  is  e.  7°  S.E.  of  £  is 
0  (3)-  9i°  N-E-  of  (9  is  ^  (3).  7°  N.E.  of  2  is  a  (2). 
13°  due  N.  of  a  is  ft  (2).  17°  due  E.  of  a  is  y  (3). 

PERSEUS. — a  (2)  is  the  brightest  star  in  this  constella- 
tion, and  is  20°  E.  and  somewhat  N.  from  Capella.  It 
lies  nearly  midway  between  two  third- mag.  stars,  forming 
with  them  a  curved  line  about  8°  long.  They  are  y  (N.) 
and  d  (S.).  12^°  nearly  due  S.  of  y  is  ft.  9°  nearly  due 
E.  of  ft  is  s  (3).  8°  nearly  due  S.  of  e  is  2  (3).  3^°  due 
N.  of  ft  is  H  (4). 

PISCES. — a  can  only  be  aligned  from  a  neighboring 
constellation.  It  is  a  third-mag,  star  10°  nearly  due  W. 
of  y  Ceti. 

SAGITTA. — A  line  from  Wega  through  y  Lyrae  and 
i7j°  on  reaches  two  fourth-mag,  stars  about  i°  apart. 
They  are  a  (N.)  and  ft  (S.). 

SAGITTARIUS. — 23  J°  E.  and  4°  S.  from  Antares  is  a  third- 
mag,  star,  which  is  y.  3}°  E.  of  y,  a  trifle  N.,  is  d  (3). 
5°  N.E.  of  d  is  A  (3).  6|°  E.,  a  little  S.  of  A,  is  a.  6J° 
N.E.  of  a  is  n  (3).  4°  S.  and  2°  E.  of  0  is  Z  (3).  6° 
N.W.  of  A  is  fjL  (4). 

SCORPIO. — 2j°  N.W.  of  Antares  is  a  (3),  and  6°  further, 
in  the  same  line,  is  d  (3).  ft  (2)  is  3°  N.E.  of  d.  21° 
W.,  a  little  N.  from  Antares,  is  y  (3). 

SERPENS. — 22°  N.  and  a  little  W.  from  Antares  will  be 
found  two  third-mag,  stars  ij°  apart,  which  belong  to 
Ophiucus.  12°  N.W.  from  these  will  be  found  a  similar 


90  THE    AMATEUR    TELESCOPIST'S   HANDBOOK. 

but  wider  pair.  These  are  a  (2)  and  8  (3).  8°  due  S.  of 
s  is  )A  (3).  i°  N.E.  of  a  is  A  (4).  9°  nearly  due  N.  of 
a  is  ft  (3).  9j°  S.  and  2J°  W.  from  £  Aquilae  is  0  (4), 
and  11°  S.W.  of  (9  is  77  (4). 

TAURUS. — nj°  due  N.  of  the  group  in  Orion's  head  is 
Z  (3).  8°  N.  and  3°  W.  of  £  is  ft  (2).  7°  N.,  a  little  E. 
from  a,  is  r  (4). 

TRIANGULUM. — 7^°  S.,  a  little  E.  from  y  Andromedae, 
is/?  (3).  7*°S.W.of/?is«(4). 

URSA  MAJOR. — The  stars  in  the  "  Dipper,"  from  the 
Pointer  nearest  the  Pole,  are  <*,  /?,  y,  6,  f,  £,  and  77.  A  line 
from  tf  to  /?  and  about  20°  on  will  pass  near  two  third-mag, 
stars  ii°  apart.  These  are  z  (N.)  and  «(S.).  6°  N.E.  of 
them  is  0  (3).  About  12°  S.E.  of  6  is  another  pair  of 
third-mag,  stars,  which  are  A  (N.)  and  /*  (S.).  A  line  from 
Polaris  through  the  "  Dipper  "  bowl  and  about  22°  on  will 
reach  a  third  pair  of  stars,  mags.  3  and  4,  of  which  the 
northern  one  is  v. 

VIRGO.— 6°  N.W.  from  Spica  is  0  (4).  8°  N.W.  from 
6  is  y  (3).  5i°  W.  of  y  is  7;  (3).  *  7^°  W.  and  somewhat 
N.  from  77  is  ft  (3).  6°  N.E.  of  y  is  d  (3),  and  8°  N.,  a 
little  E.  from  d,  is  e  (3). 

A  DESCRIPTIVE  CATALOGUE  OF  FOUR  HUN- 
DRED  AND   SIXTY-EIGHT    CELESTIAL 
OBJECTS. 

ANDROMEDA. 

An  extensive  northern  constellation.  Mean  R.  A.,  i2h. 
5om.  ;  Dec.,  +  26°  ;  stars,  226. 

a.  (Alpheratz.)  R.  A.,  oh.  2m.  415.;  Dec., +  28°  29.2'. 
A  difficult  double.  A  2,  white;  B  n,  purplish.  D.,  70.2". 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  QI 

/?.  (Merach.)  R.  A.,  ih.  301.  345.;  Dec.,  +  35°  2.3'.  A 
bright  star,  with  distant  companion.  A  2,  fine  yellow  ;  B 
10,  pale  blue.  D.,  304". 

y.  (Almaack.)  R.  A.,  ih.  57m.  8s.;  Dec.,  +  4°  48.1'. 
A  splendid  double  ;  really  triple,  but  not  in  a  small  tele- 
scope. A  3^,  orange  ;  B  5^,  emerald  green.  D.,  10.1". 

6.  R.  A.,  oh.  33m.  265.;  Dec.,  +  30°  15.5'.  A  bright 
star,  with  a  difficult  distant  companion.  A  3,  orange  ;  B 
10,  dusky.  D.,  229.1". 

n.  R.  A.,  oh.  31  m.  os.;  Dec., +  33°  6.8'.  A  fine  double. 
A  4^,  fine  white  ;  B  9,  blue.  D.,  35.1".  Line  from  a  Pegasi 
to  a  Andromedae  and  8°  beyond,  a  trifle  to  the  N. 

4  Birm.  R.  A.,  oh.  i4m.  55.;  Dec.,  +  44°  5.9'.  A  fine 
red  eighth-mag,  star.  Line  from  a  Cassiopeae  to  £  Cass. 
and  10°  on. 

56.  R.  A.,  ih.  49m.  375.;  Dec.,  +  36°  42.2'.  A  neat 
double.  Both  6,  both  yellow.  D.,  181.6".  Probably  a 
binary.  6°  from  y  on  line  to  a  Trianguli. 

240  P.  XXIII.  R.  A.,23h.52m.  285.;  Dec.,  +  23°  44.3'. 
.  fine  double.  A  8|,  pale  white  ;  B  9,  yellowish.  D.,  9.1". 
Knott,  in  1862,  pronounced  B  "most  decidedly  blue." 
Line  from  the  ^word-handle  of  Perseus  through  a  and 
5°  on. 

R.  R.  A.  (1880),  oh.  1 8m.;  Dec.,  +  37°  55'.  A  rich 
orange  star,  which  varies  in  405  days  from  about  mag.  6 
to  invisibility.  About  10°  from  a  on  line  to  B  Cass. 

31  M.  (H.,  116.)  R.  A.,  oh.  36m.  473.;  Dec., +40°  40.1'. 
The  Great  Nebula  in  Andromeda,  justly  described  by 
Smyth  as  "  overpowering."  Under  favorable  circum- 
stances it  can  be  seen  by  the  naked  eye  as  a  faint  cloudy 
spot.  In  shape  it  is  somewhat  oval,  with  considerably 
greater  brilliancy  at  the  centre  than  at  the  edges.  Its 
light  probably  requires  about  6,000  years  to  reach  us.  It 


92  THE    AMATEUR    TELESCOPIST's    HANDBOOK. 

has  never  been  resolved,  but,  according  to  Huggins,  is 
not  gaseous.  Its  spectrum,  however,  is  suddenly  cut  off 
at  the  red  end — a  most  mysterious  and  inexplicable  cir- 
cumstance. 

This  nebula  has  a  small  nebula  (32  M.),  25'  S.  of  it,  of 
much  feebler  light.  The  major  axis  of  the  Great  Nebula 
is  about  40'  in  length,  and  the  minor  axis  about  15'.  i^° 
due  W.  of  v. 

32  J§L  VII.  (H.,  457.)  R.A.,  ih.5im.  145.;  Dec., +  37° 
7.6'.  A  large,  rich  cluster,  about  30'  in  diameter.  Line 
from  a  to  ft  and  8°  on. 

ANSER  ET  VULPECULA  (THE  GOOSE  AND  Fox). 

A  modern  constellation  constructed  by  Hevelius.  Mean 
R.  A.,  2oh.;  Dec.,  +  25°  ;  stars,  126. 

6  and  8.  R.  A.,  19!!.  2401.  8s. ;  Dec.,  -f  24°  26.6'.  A  pair  of 
stars.  A  4,  deep  yellow  ;  B  5,  yellowish.  D.,  403.5".  Line 
from  Altair  through  a  and  (3  Sagittae  and  7j°  on. 

2504  2.  R.  A.,  i9h.  i6m.  95.;  Dec.,  +  18°  56.4'.  An  in- 
teresting double.  A  6-J-,  yellowish  white  ;  B  8^,  bluish.  D., 
8.9".  Duner  found  these  stars  sometimes  white,  some- 
times yellow.  Line  from  Wega  midway  between  ft  Lyr. 
and  y  Lyr.  and  16°  on. 

320  P.  XIX.  R.  A.,  i9h.  48m.  315.;  Dec.,  +  20°  3'.  A 
wide  double.  Both  7,  both  white.  D.,  42.3".  Line  from 
Wega  to  ft  Cygni  and  9°  on. 

2769.2*.  R.  A.,  2 ih.  5m.  355.;  Dec., +  22°  0.4'.  A  pretty 
double.  A  7,  B  8,  both  white.  D.,  18.2".  Line  from  a 
Cephei  through  £  Cygni  and  8°  on. 

R.  R.  A.  (1880),  2oh.  59m.;  Dec., +  23°  21'.  Aredstar, 
variable  in  about  140  days  from  mag.  8  to  invisibility  with 


THE    AMATEUR    TELESCOPIST'S   HANDBOOK.  93 

the  most  powerful  telescope.  2°  from  last  object  on  line 
to  y  Lyrse. 

21  ]£  VIII.  (H.,  4497.)  R.  A.,  i9h.  22m.  345.;  Dec., 
+  24°  55.1'.  A  large  straggling  cluster,  whose  brightest 
members  assume  the  form  of  a  Greek  £1.  3°  from  ft 
Cyg.  on  line  to  Attair. 

27  M.  (H.,4532.)  R.  A.,  igh.  54m.  485.;  Dec., +  22°  25'. 
The  singular  "  Dumb-bell  "  Nebula.  This  extraordinary 
binuclear  nebula  has,  in  a  small  telescope,  an  oval  shape, 
but  it  bears  magnifying  well,  and  with  a  good  2^-inch 
glass  the  duplicity  of  the  nucleus  may  be  seen.  It  is  14° 
from  Altair  on  line  to  a  Cephei. 


ANTINOUS. 

A  constellation  frequently  joined  with  Aquila.  Mean 
R.  A.,  i9h.  35m.;  Dec.,  —  3  ;  stars  (with  Aquila),  276. 

274  P.  XVIII.  R.  A.,  i8h.  57m.  55.;  Dec.,  — o°5i.9'.  A 
double  star  ;  triple  in  large  instruments.  Both  9,  both 
white.  D.,  23.8".  4°  from  A,  a  trifle  E.  of  a  line  from  A 
to  6  Serpentis. 

2654  2.  R.  A.,  2oh.  9m.  245.;  Dec.,  — 3°  50.4'.  A  beau- 
tiful double.  A  6|,  B  8£.  Both  white,  according  to 
Smyth,  but  according  to  Webb,  yellow  and  blue.  D.,  1 1.8". 
Line  from  Altair  through  6  Aquilae  and  2 J°  on. 

140  P.  XX.  R.  A.,  2oh.  2im.  465.;  Dec.,  —  2°  28.3'.  A 
wide  double  in  a  very  fine  field.  A  71,  B  8,  both  white. 
D.,  59.6".  Line  from  e  Pegasi  to  6  Aquilae  and  3°  on. 

ii  M.  (H.,4437.)  R.  A.,  i8h.  45111.  135.;  Dec.,  -  6° 
24.1'.  A  splendid  cluster,  nebulous  in  a  small  telescope. 
Smyth  likens  it  in  shape  to  a  flight  of  wild  ducks.  3f  ° 
from  A  on  line  to  rj  Ophiuci. 


94  THE    AMATEUR    TELESCOPIST  S   HANDBOOK. 


AQUARIUS  (THE  WATER-BEARER). 

A  not  very  conspicuous  constellation,  containing  no  stars 
above  the  third  magnitude,  but  astronomically  important 
owing  to  its  position  in  the  Zodiac  and  its  telescopic 
richness.  Mean  R.  A.,  2ih.  5001. ;  Dec.,  —  10° ;  stars,  343. 

r2.  R.  A.,  22h.  43m.  473.;  Dec.,  —  14°  10.3'.  A 
beautiful  orange-red  star,  with  a  distant  bluish  companion 
of  mag.  9.  The  primary  is  of  mag.  5 — a  lovely  object. 
D->  I33-4"-  2f°  from  #  on  line  to  y. 

^}\  R.A.,  23h.  rom.  75.;  Dec.,  —  9°  41.3'.  Abeautiful 
double.  A  5^,  orange  tint ;  B  9,  sky  blue.  D.,  49.9". 
y  Capricorni  and  6  Capr.  point  to  this  object,  22^°  from 
the  latter. 

R.  R.  A.  (1880),  23h.  38m.;  Dec.,  —  15°  57'.  A  deep- 
red  star,  variable  in  about  390  days  from  mag.  6  to  12^. 
Line  from  $  Capr.  to  d  Aquarii  and  12^°  on. 

29.  R.  A.,  2ih.  56m.  255.;  Dec.,  —  17°  29.7'.  A 
beautiful  close  double.  Both  7,  both  white.  D.,  3.6". 
Line  from  i  Capr.  to  y  Capr.  and  5^°  on. 

41.  R.  A.,  22h.  8m.  145.;  Dec.,  —  21°  37.3'.  An  ele- 
gant double.  A  6,  topaz  yellow  ;  B  8-J,  cerulean  blue.  D., 
5.1".  8£°  from  d  Capr.  on  line  to  Fomalhaut. 

53.  R.  A.,  22h.  2om.  345.;  Dec.,  —  17°  18'.  Abeau- 
tiful double.  Both  6£,  both  pale  white.  D.,  7.8".  Line 
from  i  Capricorni  to  y  Capr.  and  n-J°  on. 

94.  R.  A.,  23h.  i3m.  i8s.;  Dec.,  —  14°  3.4'.  A  lovely 
double.  A  6,  pale  rose  tint ;  B  8-J,  light  emerald.  D., 
13.8".  6^°  from  d  on  line  to  i  Ceti. 

107.  R.  A.,  23h.  4om.  i8s. ;  Dec.,  —  19  17.5'.  A  very 
beautiful  double.  A  6,  bright  white  ;  B  7^,  blue.  D., 
5.8".  Line  from  y  to  A  and  17°  on. 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  95 

2913  2.  R.  A.,  22h.  24m.  455.;  Dec.,  —  8°  40.7'.  A 
pretty  double.  A  y|,  white  ;  B  8-J,  reddish.  D.,  7.9". 
7-J°  from  y  on  line  to  Fomalhaut. 

219  P.  XXII.  R.  A.,  22h.  42m.  ios.;  Dec.,  —  4°  47.8'. 
A  triple  star.  A  7^,  yellow ;  B  8,  C  9,  both  flushed 
white.  D.,  AB  3.8",  AC  48.6".  6£°  from  2  on  line  to  ip. 

1  ip  IV.     (H.,  4628.)     R.  A.,  20  h.  58m.  ios.;  Dec.,  - 
11°  47.7'.     A  planetary  nebula  of  a  pale-blue  color,  bright 
to  its  edges  and  about  20"  in  diameter.     "  One  of  the 
finest  specimens  of  these  extraordinary  bodies."    (Webb.) 
Owing  to  its   appearance  in  his  telescope,  Lord  Rosse 
called  this  the  Saturn   nebula,  and  Lassell  saw  it  as  an 
elliptical  ring  with  a  star  in  the  centre.     It   yielded   to 
Dr.    Huggins   a   gaseous    spectrum.      According   to    Sir 
John  Herschel,  if  this  object  be  only  as  far  distant  from 
us  as  the  stars — and  its  distance  is  probably  enormously 
greater — its   dimensions   must  be  such  as  would  fill  the 
whole  orbit  of   Uranus.     A  globular   body  of  such  size 
could  contain  more   than   sixty-eight   thousand    millions 
of  globes  as  large  as  our  sun.     i°  due  W.  of  v. 

2  M.     (H.,  4678.)     R.  A.,  2ih.  27m.  445.;   Dec.,  -  i° 
19.  i'.   A  fine  globular  cluster,  nebulous  in  all  but  large  tele- 
scopes.    The  total  light   yielded  by  it  does  not  exceed 
that  of  a  star  of  the  sixth  magnitude.     In  the  Herschel 
telescope  it  resembled  a  heap  of  fine  sand.     Huggins  finds 
it  gaseous.     Diameter,  5'  or  6'.     Line  from  2,  Capricorn! 
to  ft  Aquarii  and  5°  beyond. 


AQUILA  (THE  EAGLE). 

A  rich  and  beautiful  constellation,  lying  directly  in  the 
Milky  Way.     It  is  frequently  joined  with  Antinoiis  as  one 


96  THE    AMATEUR    TELESCOPIST's    HANDBOOK. 

asterism.     Mean   R.  A.,  i6h.    2om. ;   Dec.,   +    10  ;   stars 
(with  Antinoiis),  276. 

a.  (Altair.)  R,  A.,  i9h.  4501.  248.;  Dec.,  +  8°  34.2'. 
A  brilliant  star  with  a  distant  companion.  A  i^,  pale 
yellow;  B  10,  violet  tint.  D.,  156.1".  Will  be  found 
very  difficult  in  a  small  telescope. 

ft.  (Alshain.)  R.  A.,  iph.  49m.  545.;  Dec.,  +  6°  8.3'. 
A  star  with  several  small  companions.  Mag.,  3^.  The 
principal  companion  is  of  mag.  10,  pale  gray,  and  presents 
a  singular  contrast  to  the  delicate  orange  of  the  primary. 
D.,  151.7".  Difficult. 

R.  R.  A.  (1880),  19!!.  im.;  Dec.,  +  8°.3;.  Adeep-red 
star,  varying  in  345  days  from  mag.  6.5  to  n.  (Arge- 
lander.)  5!°  from  £  on  line  to  A. 

T.  R.  A.,  i8h.  4om.  265.;  Dec.,  +  8°  38.1'.  A  pale 
ruby  star,  varying  in  about  four  months  from  mag.  9 
to  9^.  7°  from  e  on  line  to  rj  Serpentis. 

15.  R.  A.,  i8h.  59m.  95.;  Dec.,  —  4°  11.7'.  A  fine 
double.  A  6,  yellowish;  B  7^,  lilac.  D.,  37.1".  Other 
stars  in  field.  i°  N.,  a  little  W.  of  A. 

57.  R,  A.,  190.  48m.  405.;  Dec.,  —  8°  30.8'.  A  fine 
double.  A  6^,  B  7,  both  blue  according  to  Smyth,  but 
observers  differ  to  a  remarkable  extent  as  to  these  colors, 
and  Webb  urges  telescopists  to  watch  this  pair.  D.,  35.6". 
Line  from  a  to  rj  and  9^°  on. 

483  Birm.  R.  A.,  i8h.  5501.  325.;  Dec.,  —  5°  50.9'.  A 
very  deep-red  star  of  mag.  7^.  "  A  fine  specimen  of  a  re- 
markable and  beautiful  class."  (Webb.)  if  S.W.  of  A. 

302  P.  XVIII.  R.  A.,  i9h.  om.  255.;  Dec.,  +  6°  23'. 
A  very  neat  double.  A  7^,  lucid  white  ;  B  9,  cerulean 
blue.  D.,  9.9".  Line  from  rj  to  6  Serpentis  and  4°  on. 

241  P.  XIX.     R.  A.,  i9h.  37m.  265.;    Dec.,  +  8°  7.3'. 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK.  97 

A  delicate  double.  A  7^,  pale  topaz  ;  B  9^,  lilac.  D., 
26.7'.  It  is  4°  E.  and  a  little  S.  from  a,  and  just  above 
/*,  a  fifth-mag,  star. 

43  P.  XX.  R.  A.,  2oh.  8m.  465.;  Dec.,  +  6°  14.8'.  A 
double  star.  A  6.8,  B  7.2,  both  lucid  white.  Line  from 
a  to  £,  the  fifth-mag,  star,  i°  S.E.  of  it  and  5°  on. 

47  ^L  I.  (H.,  4441.)  R.  A.,  i8h.  47m.  75.;  Dec.,  -  8° 
50.1'.  A  globular  cluster  6'  in  diameter.  The  component 
stars  are  small,  and  the  cluster  is  less  bright  toward  the 
centre.  A  line  from  6  through  A  and  4f°  further  on  will 
reach  a  point  40'  S.E.  of  this  cluster. 

1913  VII.  (H.  4470.)  R.  A.,  i9h.  2m.  195. ;  Dec.,  +  4° 
3.4.'  A  large  and  rich  cluster  of  stars  from  mag.  12  to 
14.  A  line  from  d  Aquilae  to  6  Serpentis  will  pass  about 
i°  S.  of  it,  4j°  from  the  former  star.  Difficult. 

2035  h.  (11.4482.)  R.  A., i ph. i im. us.;  Dec.,  — 1*6.9'. 
A  loose,  splashy  cluster  of  stars  from  mag.  9  to  1 2.  Rather 
difficult  in  a  small  telescope.  4^°  from  d  on  line  toward  A. 

4473  H.  R.  A.,  i9h.  5m.  525. ;  Dec.,  +  o°  51'.  A  re- 
markable faint  nebula,  which,  according  to  Hind,  is  vari- 
able. It  is  21°  N.  E.  of  the  last  object,  on  a  line  toward 
6  Serpentis. 

ARGO  NAVIS  (THE  SHIP  ARGO). 

A  grand  constellation,  most  of  which  is  below  the  hori- 
zon in  every  part  of  the  United  States,  much  more  in 
England.  Mean  R.  A.,  9h. ;  Dec.,  —  55°.  Stars,  540  ac- 
cording to  Bode,  and  1,330  according  to  Sir  T.  Brisbane. 

149  P.  VII.  R.  A.,  7h.  29m.  405.  ;  Dec.,  —  23°  14.1'.  A 
splendid  double.  Both  mag.  6,  both  topaz.  D.,  9."  Line 
from  Pollux  to  Procyon  and  28°  beyond,  or  from  Orion's 
sword  through  Sirius  and  14°  on. 

7 


98  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

1138  2.  R.  A.,  yh.  4001.  263.  ;  Dec.,  —  14°  25.4'.  A 
double  star.  A  7,  silvery  white  ;  B  7^,  pale  white.  Line 
from  a  Leporis  through  Sirius  and  as  far  again  to  the  E. 
Almost  in  the  field  is  4  Argo  Navis,  a  yellow  5th  mag.  star. 

15219  Lalande.  R.  A.,  7h.  42m.  455. ;  Dec.,  —  15°  44.5'. 
A  fine  pair  of  stars.  Both  mag.  6J,  both  deep  orange. 
D.,  127.8".  A  line  from  /?  Canis  Majoris  carried  i°  S. 
of  Sirius  and  15^-°  further  on  will  strike  it. 

72  P.  VIII.  R.  A.,  8h.  2om.  i8s. ;  Dec.,  —  23°  41.3'.  A 
beautiful  double.  A  6,  red ;  B  9},  green.  D.,  41.9". 
Line  from  Rigel  to  Sirius  and  25^°  beyond,  and  another 
at  right  angles  N.  W.  2°. 

35  JgL  VIII.     (H.  1521.)     R.  A.,  7h.  i8m.  545.  ;  Dec., 

—  13°  2.9'.    A  cluster  large  but  little  condensed,  consisting 
of  rather  large  stars.    Line  from  /3  Canis  Majoris  through 
Sirius  and  15°  beyond. 

38  Jp  VIII.     (H.  1551.)     R.  A.,  yh.  3im.  33s.  ;  Dec., 

—  14°  14.3'.     A  splendid  field  of  stars,  somewhat  lozenge- 
shaped,  about  15'  in  diameter,  and  led  by  a  fiery  red  7th 
mag.  star.     It  contains  a  double  star,  A  7^,  B  8,  both 
bluish  white.     D.,  7.3".     Line  from  ft  Can.  Majoris,  just 
under  Sirius,  and  13°  beyond. 

46  M.  (H.  1564.)  R.  A.,  7h.  36m.  475.  ;  Dec.,  —  14°  27.3'. 
A  noble  though  rather  loose  cluster,  more  than  30'  in 
diameter,  composed  of  stars  from  mag.  8  to  13,  making 
a  splendid  glow.  It  contains  a  delicate  double,  A  8J, 
B  n,  both  white.  D.,  15".  "  The  impression  left  on  the 
senses  is  that  of  awful  vastness  and  bewildering  distance." 
This  object  is  i°  20'  W.  and  a  little  S.  of  the  last  men- 
tioned. 

64  W  IV.     (H.  1567.)     R.  A.,  7  h.  36m.  595.  ;  Dec.,  - 
17°  56.6'.     A  bright  planetary  nebula.     With  a  power  of 
64  it  resembles  a  dull  8th  mag.  star.    With  higher  powers 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK.  99 

it  presents  a  bright  undefined  disk.  Line  from  3  Can. 
Maj.  through  Sirius  and  14°  beyond. 

93  M.  R.  A.,  7h.  3901.  515.;  Dec., — 17°  56.6'.  A 
small  galaxy  cluster  8'  in  diameter.  The  components 
range  in  magnitude  from  7  to  [2,  and  the  group  is  com- 
pared by  Smyth  to  a  star-fish.  Line  from  Orion's  sword- 
cluster  through  Sirius  and  16°  beyond.  "  The  unlucky 
Chevalier  d'Angos,  of  the  Grand  Master's  Observatory  at 
the  summit  of  the  palace  at  Malta,  mistook  this  object 
for  a  comet ;  from  which,  and  even  still  more  suspicious 
assertions,  my  excellent  friend  Baron  de  Zach  was  in- 
duced to  term  any  egregious  astronomical  blunders  Ango- 
siades"  (Smyth.) 

ii  ]£  VII.  (H.  1630.)  R.  A.,8h.  501.  3is.;  Dec.,- 
12°  32'.  A  large  and  loose  but  rich  field.  A  close  dou- 
ble in  the  centre,  and  a  bright  yellow  6th  mag.  star  sf. 
Line  from  fi  Can.  Maj.  just  below  Sirius  and  21^°  further 
on. 

63  I£  VII.  (H.  1678.)  R.  A.,  8h.  32m.  345.;  Dec., 
—  29°  33.6'.  A  compressed  cluster.  Line  from  Rigel 
through  Sirius  and  30  J°  beyond. 


ARIES  (THE  RAM). 

An  inconspicuous,  but  astronomically  important  con- 
stellation. Mean  R.  A.,  2h.  25';  Dec.,  +  13°;  stars,  148. 

a.  (Hamal.)  R.  A.,  2h,  om.  585.;  Dec.,  +  22056'.  A 
star  with  a  telescopic  companion.  A  3,  yellow  ;  B  11, 
purple.  Difference  of  R.  A.,  19.55. 

/?.  (Sheratan.)  R.  A.,  ih.  48m.  335.;  Dec., +  20°  16.2'. 
A  pretty  double,  but  will  prove  decidedly  difficult  in  a 


IOO  THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

small  telescope.     A  3,  pearly  white  ;  B  n,  dusky.     Differ- 
ence of  R.  A.,  7.45. 

y.  (Mesarthim.)  R.  A.,  ih.  471*1.  295.;  Dec.,-f  18° 
45.3'.  A  fine  double.  A  4^,  white;  B  51,  pale  gray.  D., 

8.3*-. 

A.  R.  A.,  ih.  5im.  475.;  Dec.,  +  23°  3.6'.  A  fine  dou- 
ble. A  5^,  yellowish  white  ;  B  8,  blue.  D.,  37. 5".  This 
star  is  the  apex  of  an  oblique  triangle  of  which  a  and  ft 
form  the  base. 

14.  R.  A.,  2h.  3m.  95.;  Dec,,  +  25°  25.3'.  A  beautiful 
triple.  A  5  J,  white  ;  B  loj,  blue  ;  C  9,  lilac.  D.,  AB 
82.6",  AC  106.5".  Tm's  star  is  2°  40'  N.  and  a  little  W. 
of  a. 

30.  R.  A.,  2h.  3om.  375.  ;  Dec.,  +  24°  10.2'.  A  fine 
double.  A  6,  topaz  yellow  ;  B  7,  pale  gray.  D.,  38.3". 
Line  from  y  Pegasi  through  Hamal  and  7°  beyond. 

41.  R.  A.,  2h.  43m.  305.;  Dec.,+  26°  48.5'.  A  coarse 
quadruple  star,  which  our  observer  will  probably  see 
triple  or  even  only  double.  A  3,  white  ;  B  13,  deep  blue; 
C  n,  lurid  ;  D  9,  pale  gray.  D.,  AB  21.2",  AC  34",  AD 
125.9".  This  star  is  the  lucida  of  the  scarcely  recognized 
constellation  Musca  Borealis.  6J°  from  s  on  line  to  y 
Androm. 

AURIGA    (THE  CHARIOTEER). 

A  fine  constellation,  rich  in  telescopic  objects.  Mean 
R.  A.,  5h.  27m.;  Dec.,  +  42°  ;  stars,  239. 

a.  (Capella.)  R.  A.,  sh.  8m.  335.;  Dec.,+  45°  53.5'. 
A  splendid  star  of  mag.  i,  bright  white,  with  four  distant 
companions,  of  which  only  one — E.  10,  D.  158"— will  be 
seen  in  a  small  telescope,  and  then  only  with  much  diffi- 
culty. 


THE    AMATEUR    TELESCOPIST's 

ft.  (Menkalinan.)  R.  A.,  5h.  51111.  285.;  Dec.,  +  44° 
56'.  A  beautiful  star  with  a  distant  companion.  A  2, 
lucid  yellow  ;  B  ioj,  bluish.  D.,  184". 

6.  R.  A.,  5h.  52m.  125. ;  Dec.,  +  37°  12.4'.  A  quad- 
ruple group.  A  4,  brilliant  lilac ;  B  yj,  C  10,  pale  yel- 
low ;  Dp,  yellowish.  D.,  AB  2.08",  AC 45. 5",  AD  125.1". 

A.  R.  A.,  5h.  nm.  225.;  Dec.,  +  40°  0.6'.  A  triple 
group.  A  5,  pale  yellow  ;  B  13,  C  9^,  plum-color.  D., 
AB  40.4",  AC  121.5".  Many  stars  in  field.  This  star  is 
about  5°  from  Capella  on  a  line  toward  Bellatrix. 

GO.  R.  A.,  4h.  5im.  475.;  Dec.,  +  37°  43.4'.  A  beau- 
tiful double.  A  4,  pale  red  ;  B  8,  light  blue.  D.,  5.9'. 
About  one-third  the  distance  between  Capella  and  the 
Hyades. 

26.  R.  A.,  5h.  3im.  345.;  Dec.,  +  30°  25.6'.  A  fine 
double.  A  5,  pale  white  ;  B  8,  violet.  D.,  12.3".  Line 
from  s  Orionis  through  2,  Tauri,  and  something  less  than 
10°  on. 

41.  R.  A.,  6h.  3m.  ics. ;  Dec.,  +  48°  44',  A  neat  dou- 
ble. A  6,  silvery  white  ;  B  7,  pale  violet.  D..  7.7".  Line 
from  (3  Tauri  through  /3  Aurigse  and  4°  beyond. 

56.  R.  A.,  6h.  38m.  488.;  Dec.,  +  43°  41.1'.  A  double 
star.  A  6,  silvery  white  ;  B  8J,  lilac.  Just  north  of  a  line 
from  a  through  /?,  and  extended  as  far  beyond. 

4  B.  R.  A.,  4h.  3im.  415.;  Dec.,  +  26°  43.7'.  A  pretty 
double.  Both  mag.  7,  both  double.  D.,  3.7".  Line  from 
Capella  through  £  and  18°  on. 

96  B.  R.  A.,  5h.  23m.  435.;  Dec.,  +  49°  18.3'.  A  neat 
double.  Both  mag.  8,  both  very  white.  D.,  7.7".  About 
4°  from  Capella  on  line  towards  ft  Urs.  Maj. 

2139  B-  A-  c-  R-  A-  (l87°),  6n-  27m-  36s-;  Dec->  +  38° 
32.8'.  A  superb  orange-red  star,  of  mag.  6.5.  Line  from 
a  2%°  E.  of  ft  and  8°  further  on. 


roz        TbE  AMATEUR  TELESCOPIST'S  HANDBOOK. 

33  J§L  VII.  (H.  1067.)  R.  A.,  5h.  12111.  95.;  Dec.,  +  39° 
13.7'.  A  rich  field  of  small  stars,  the  most  prominent 
among  which  is  a  bright  orange  7^  mag.  star.  About 
7°  from  Aldebaran  on  a  line  towards  Bellatrix. 

39]£VII.  (H.  1114.)  R.A.,  5h.  2om.38s.;  Dec., +  35° 
13.3.'  A  compressed  cluster  about  3'  in  diameter,  12° 
from  Capella  on  a  line  towards  Betelgeuse.  This  cluster 
is  in  a  rich  neighborhood,  there  being  no  less  than  four 
others  so  near  it  that  they  may  all  be  included  in  a  circle 
4°  in  diameter. 

38  M.  (H.  1119.)  R.  A.,  5h.  22m.  2s.;  Dec.,  +  35° 
44.1'.  A  rich  cluster  10'  in  diameter,  very  near  the  last- 
mentioned  one  towards  the  N.  and  a  little  W.  The  most 
clustering  part  forms  an  oblique  cross  with  a  pair  of  larger 
stars  in  each  arm,  and  a  conspicuous  one  in  the  centre. 
Line  from  Rigel  through  ft  Tauri  and  about  7°  beyond. 

36  M.     (H.  1166.)     R.  A.,  5h.  29m.  2s.;  Dec.,  +  34° 
4.2'.     A  splendid  though  open  cluster  ;  another  of  the 
above  group.     In  the  cluster  is  a  neat  double  star.     A  8, 
B  9,  both  white.     D.,  12".     Line  from  middle  of  Orion's 
belt  through  2  Tauri  and  about  13°  beyond. 

37  M.     (H.  1295.)     R.  A.,  511.  45m.  25.;  Dec.,  -f  32° 
31.3'.     A   magnificent   cluster,    24'   in   diameter.     "  The 
whole  field  strewed,  as  it  were,  with  sparkling  gold-dust." 
(Smyth.)     "  Extremely  beautiful,  one  of  the  finest  of  its 
class.     Gaze  at  it  well  and  long."     (Webb.)     "  Wonder- 
ful loops  and  curved  lines  of  stars."    (Rosse.)    Line  from 
Aldebaran  through  fi  Tauri  and  7°  on. 

BOOTES. 

A  fine  and  rich  constellation.  Mean  R.  A.,  i4h.  3001.; 
Dec.,  +  3°°-  Stars,  319. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.          103 

a.  (Arcturus.)  R.  A.,  i4h.  lorn.  395.;  Dec.,  +  19° 
45.7'.  A  magnificent  star,  usually  rated  as  next  to  Sirius 
in  brilliancy.  It  has  a  minute  distant  lilac  companion  of 
the  nth  magnitude,  which  is  quite  beyond  the  powers 
of  a  small  telescope. 

d.  R.  A.,  i5h.  nm.  33.;  Dec.,  +  33°  43.7'.  Star  with 
distant  companion.  A  3^,  pale  yellow  ;  B  8^,  light  blue. 
D.,  104.6". 

f.  R.  A.,  i4h.  4om.  us.;  Dec.,  +  27°  32.2'.  A  famous 
and  most  beautiful  double  which  Struve  designated  as 
"  Pulcherrima."  A3,  pale  orange;  B  7,  emerald  green, 
the  colors  in  lovely  contrast.  D.,  2.77".  Line  from 
Mizar  (8>  Urs.  Maj.)  through  rj.  Urs.  Maj.  to  the  star  in 
question,  which  is  about  midway  between  Arcturus  and 
a  Coronae  Borealis. 

H.  R.  A.,  i4h.  9m.  315.;  Dec.,  52°  18.1'.  A  fine 
double.  A  5!,  pale  white;  B  8,  bluish.  D.,  12.9". 
Line  from  s  Urs.  Maj.  through  Mizar  and  6°  further 
on. 

//.  R.  A.,  ish.  2om.  2 is.;  Dec.,  +  37°  45-8'-  A 
double  in  a  small  telescope,  but  triple  in  a  larger  one. 
A  4,  flushed  white  ;  B  8,  greenish  white.  D,,  108.5".  A 
line  from  rj  Urs.  Maj.  through  ft  Bootis  and  4°  beyond 
will  pass  within  i°  of  this  star. 

£.  R.  A.,  i4h.  46m.  i8s.;  Dec.,  +  19°  33.6'.  A  fine 
binary  star.  A  3^,  orange  ;  B  6^,  purple.  D.,  4.19".  8-J° 
from  a  on  line  to  /?  Serpentis. 

n.  R.  A.,  i4h.  35m.  335.;  Dec.,  +  16°  53.5'.  A  fine 
double.  A  3!,  B  6,  both  white.  D.,  5.96".  7°  from  Arc- 
turus on  a  line  towards  a  Serpentis. 

44.  R.  A.,  i5h.  om.  us.;  Dec.,  -f  48°  5'.  A  remark- 
able and  highly  interesting  binary  with  a  period  of  about 
261  years.  A  5,  pale  white  ;  B  6,  lucid  gray.  D.,  4.99". 


104        THE  AMATEUR  TELESCOPIST'S  HANDBOOK. 

Sir  W.  Herschel  calls  this  a  miniature  of  Castor.  7^°  from 
ft  on  line  towards  the  N.  pole. 

220  P.  XIII.  R.  A.,  13!!.  45m.  125.;  Dec.,  +  21°  49.4'. 
A  wide  double.  A  ;£,  B  8,  both  flushed  white.  D.,  85.8". 
In  the  same  field  is  6  Bootis.  This  star  is  6°  from  Arc- 
turus  towards  Coma  Berenices. 

1850  2.  R.  A.,  i4h.  23m.  425.;  Dec.,  +  28°  46.7'.  A 
pretty  double.  A  6£,  B  7,  both  very  white.  D.,  25.2". 
It  is  about  i°  W.  of  a  line  from  a  to  ft,  and  8°  from  the 
former. 

CAMELOPARDUS. 

A  large  but  not  very  important  or  conspicuous  modern 
constellation.  Mean  R.  A.,  5h.;  Dec.,  70°  ;  stars,  211. 

i.  R.  A.,  4h.  i9m.  233.;  Dec.,  +  53°  33.3'.  A  neat 
double.  A  7^,  white  ;  B  8^,  sapphire  blue.  D.,  10.2". 
Nearly  midway  between  a  Persei  and  d  Aurigae. 

97  P.  III.  R.  A.,  3h.  33m.  38s.;  Dec.,  +  59°  &*'•  A 
lovely  but  rather  difficult  double.  A  6,  orange  with  scar- 
let glare  ;  B  9,  blue.  D.,  55.6".  15°  from  6  Persei  on 
line  towards  Polaris. 

485  2.  R.  A.,  3h.  58m.  155.;  Dec.,  +  62°  3.4'.  A 
pretty  double.  Both  6^  ;  A  white,  B  bluish  white.  D., 
17.8".  Line  from  a  Cassiopeae  through  d  Cass.  and  15° 
beyond. 

269  P.  IV.  R.  A.,  5h.  4m.  265.;  Dec.,  +  79°  6.1'.  A 
fine  double.  A  5^,  light  yellow  ;  B  9,  pale  blue.  D., 
20.2".  Line  from  j3  Draconis  through  Polaris  and  10°  on. 

159  P.  VII.  R.  A.,  yh.  35m.  265.;  Dec.,  +  65°  24.9'. 
A  fine  double.  Both  mag.  8,  both  white.  D.,  15.6".  In 
a  rich  neighborhood.  Line  from  Capella  to  6  Aurigae  and 
15°  beyond. 


THE    AMATEUR    TELESCOPISl's   HANDBOOK.  105 


CANCER  (THE  CRAB). 

A  constellation  of  little  brilliancy,  but  important  from 
its  position  in  the  zodiac.  Mean  R.  A.,  8h.  2501.;  Dec., 
+  8°  ;  stars,  179. 

6.  R.  A.,  8h.  25m.  208.;  Dec.,  18°  28.1'.  A  star  with  a 
rather  dull  companion,  which  latter,  however,  is  of  interest 
on  account  of  what  seems  to  be  a  gradual  decrease  in  its 
light.  A  5  J,  yellow  ;  B  9,  gray.  This  is  Smyth's  rating, 
but  Knott  pronounces  B  of  mag.  12,  and  suggests  that  it 
should  be  watched.  D.,  60.7".  A  line  from  Regulus  to  d 
Cancri  and  3°  beyond  will  come  to  a  point  i°  S.  of  this 
star. 

i.  R.  A.,  8h.  4om.  33.;  Dec.,  +  29°  9.7'.  A  beautiful 
double.  A  51,  pale  orange  ;  B  8,  clear  blue.  The  colors 
finely  contrasted.  D.,  30.5". 

118  P.  VIII.  R.  A.,  8h.  32m.  485.;  Dec.,  +  20°  4'. 
A  8,  B  8J,  both  pale  white.  D.,  57.2".  About  one-third  the 
distance  from  Pollux  to  Regulus,  about  2°  south  of  a  line 
so  drawn. 

124  P.  VIII.  R.  A.,  8h.  3301.  323.;  Dec.,  +  19°  56'.  A 
fine  triple.  A  7,  pale  yellow  ;  B  7^,  dusky  ;  C  6^,  lucid 
white.  D.,  AB  45.8",  AC  93.1".  About  £°  E.  and  a  little 
S.  of  the  last  object. 

129  P.  VIII.  R.  A.,  8h.  34m.  6s.;  Dec.,  +  20°  3.5'.  A 
beautiful  double.  A  7,  golden  yellow  ;  B  10,  blue.  D., 
20.5".  Close  to  the  east  of  the  last  object. 

211  Birm.  R.  A.,  8h.  49m.  us.;  Dec.,  +  17°  39'.  A 
fine  red  star  varying  from  mag.  7  to  y-J.  It  is  i£°  N.  E. 
of  a  line  from  a  to  #,  at  a  point  3°  from  the  latter. 

194  B.     R.  A.,  gh.  im.  ys.;  Dec.,  +  23°  24.9'.     A  pretty 


106  THE   AMATEUR    TELESCOPIST*S    HANDBOOK. 

double.  Both  7^,  both  white.  D.,  7.3".  Line  from  £ 
Leonis  through  e  Leonis  and  9°  beyond. 
•  44  M.  (H.  1681.)  R.  A.,  8h.  33m.  555.;  Dec.,  +  20° 
19.4'.  The  Praesepe,  a  noble  cluster  of  large  dimensions, 
easily  visible  to  the  naked  eye  as  a  nebulous  spot  resem- 
bling a  detached  scrap  of  the  Milky  Way.  It  is  a  superb 
object  in  the  telescope.  Draw  a  line  from  Castor  to  Pollux 
and  on  to  three  times  the  distance  between  them. 

67  M.  (H.  1712.)  R.  A.,  8h.  45m.  los. ;  Dec.,  -f  12° 
12.7'.  A  rich  clustering  mass  of  stars  of  mags.  9  and  10, 
followed  by  a  "crescent  of  stragglers."  It  is  2°  W.  of  a. 

CANES   VENATICI    (THE   HUNTING    DOGS). 

A  modern  constellation  formed  by  Hevelius.  Mean 
R.  A.,  i3h.  5m.;  Dec.,  +  40°  ;  stars,  139. 

a.  (Cor  Caroli.)  R.  A.,  i2h.  50111. 535.;  Dec.,  38°  54.7'. 
A  fine  double.  A  2j,  flushed  white  ;  B  6^,  pale  lilac. 
D.,  20". 

2.  R.  A.,  i2h.  lorn.  375.;  Dec.,  41°  16.5'.  A  beautiful 
double.  A  6,  golden  yellow  ;  B  9,  smalt  blue.  D.,  11.5". 
Line  from  Polaris  through  d  Ursae  Majoris,  and  17° 
beyond. 

1645  2.  (1880.)  A  beautiful  double,  closely  following 
a  star  (1642  ^),  in  R.  A.,  i2h.  2om. ;  Dec.,  +  45°  25'. 
A  7,  B  7^,  both  yellowish  white.  D.,  10.4".  "A  lovely 
pair  as  I  ever  saw."  (Bird.)  To  find  1642  2,  draw  a 
line  from  a  Ursae  Majoris  through  y  Urs.  Maj.  and  8J° 
beyond. 

94  M.  (H.  3258.)  R.  A.,  i2h.  45™.  43*.;  Dec.,  +  41° 
43.3'.  A  comet-like  nebula,  2.5'  in  diameter.  It  is  of  a 
fine  pale  white  color,  brightening  towards  the  centre.  2  J° 
from  a,  towards  $  Ursae  Majoris. 


*  THE    AMATEUR    TELESCOPIST*S   HANDBOOK.  107 

96  ip  I.     (H.  3437.)     R.  A.,  i3h.  sm.  515.;  Dec.,+  37° 
39.2'.     A  large  nucleated  nebula,  6'  long,  1.5'  wide.     Line 
from  /*  Ursae  Maj.  to  Cor.  Caroli  and  3^°  beyond. 

97  J$  I.     (H.  3459.)     R.  A.,  i3h.  8m.  235.;  Dec.,  +  37° 
10.8'.     A  bright  large  nebula,  brighter  towards  centre. 
About  J°  from  the  last  object,  S.  and  a  little  E. 

63  M.  (H.  3474.)  R.  A.,  i3h.  lorn.  535.;  Dec.,  +  42° 
36.7'.  A  faint  oval  nebula,  9'  or  10'  long,  and  nearly  4' 
wide,  with  a  nucleus  like  a  small  star.  Line  from  ft  Leo- 
nis  through  Cor  Caroli  and  5  J°  beyond. 

51  M.  (H.  3572.)  R.  A.,  i3h.  35m.  135.;  Dec.,  +  47° 
45.2'.  A  faint  double  nebula,  with  centres  4'  45"  apart, 
but  borders  in  contact.  In  a  5 -inch  telescope,  the 
southern  object  "  resembles  a  ghost  of  Saturn  with  its  ring 
in  a  vertical  position."  This  system  bears,  according  to 
Sir  John  Herschel,  a  strong  resemblance  to  our  own.  It 
is  one  of  the  most  celebrated  of  the  Earl  of  Rosse's  spiral 
nebulae.  It  lies  3°  from  rj  Ursse  Majoris,  on  a  line  from 
Polaris  through  £  Urs.  Maj. 

3  M.  (H.  3636.)  R.  A.,  i3h.  37m.  3s.;  Dec.,  +  28° 
55.3'.  A  brilliant  and  beautiful  globular  cluster  of  not 
less  than  1,000  small  stars,  blazing  towards  the  centre. 
A  noble  object,  5'  or  6'  in  diameter.  About  iS°  from 
s  Bootis  on  line  drawn  across  the  southern  base  of  the 
cluster  in  Coma  Berenices. 

CANTS  MAJOR  (THE  GREATER  DOG). 

A  fine  constellation,  distinguished  by  including  within 
its  boundaries  the  brightest  star  in  the  heavens.  Mean 
R.  A.,  7h.  ;  Dec.,  —  30°  ;  stars,  161. 

a.  (Sirius.)  R.  A.,  6h.  4om.  i8s. ;  Dec.,  —  16°  33.7'. 
The  Dog-star,  the  most  brilliant  and  splendid  of  all  the 
heavenly  host.  It  is  a  magnificent  object  in  the  telescope, 


Id8          THE   AMATEUR    TELESCOPIST'S   HANDBOOK. 

although  a  small  instrument  will  fail  to  show  even  its 
principal  companion.  Mr.  Proctor  thinks  this  comes  would 
be  visible  in  a  3-inch  telescope,  but  this  is  not  at  all  in 
accord  with  my  experience.  Sir  William  Herschel  says 
that  the  entrance  of  Sirius  into  the  field  of  his  4o-foot 
telescope  was  heralded  by  a  dawning  like  that  of  a 
sunrise,  and  that  its  lustre  when  within  the  field  was 
intolerable  to  the  eye. 

p.  (Mirzam.)  R.  A.,  6h.  17111.  525.  ;  Dec.,  —  17°  54.3'. 
A  bright  star  with  a  companion.  A  2  J-,  fine  white  ;  B  9, 
dusky  gray.  D.,  185.2".  Another  9  mag.  star  in  field. 

d.  (Wezen.)  R.  A.,  ;h.  3m.  555.  ;  Dec.,  -  26°  13.1'. 
A  star  with  companion.  A  3^,  light  yellow  ;  B  7^,  very 
pale.  D.,  265.9".  Other  small  stars  in  field. 

£.  (Adhara.)  R.  A.,  6h.  54m.  i8s.  ;  Dec.,  —  28°  49.3'. 
A  pale  orange  2\  mag.  star,  with  a  9  mag.  companion  at 
a  distance  of  7.7",  and  another  of  mag.  7  further  off. 
Line  from  middle  of  Orion's  belt  through  j3  and  14^°  on. 

77.  R.  A.,  7h.  i9m.  445.  ;  Dec.,  —  29°  5.3'.  A  beautiful 
star  with  distant  companion.  A  3,  pale  red  ;  B  7j,  dull 
gray.  Two  small  stars  following.  D.,  178.6".  Line 
from  fi  through  #  and  5°  on. 

rl.  R.  A.,  6h.  3im.  335.  ;  Dec.,  —  18°  34.1'.  A  neat 
double.  A  6J,  pale  garnet  ;  B  8,  gray.  D.,  17.4".  Fol- 
lowed in  sf  by  r2.  It  is  3°  S.E.  of  Sirius,  and  3^°  from 
Mirzam. 

17.  (n\)  R.  A.,  6h.  5om.  i8s.  ;  Dec.,  —  20°  15.9".  A 
wide  quadruple.  A  6,  flushed  white  ;  B  pj,  ruddy  ;  C  9^, 
ruddy;  D  10,  dusky.  D.,  AB  45",  AC  52.5",  AD  125". 
This  is  the  middle  one  of  three  small  stars  about  4^° 
S.S.E.  of  Sirius: 

22.  R.  A.  (1870),  6h.  56m.  328.  ;  Dec.,  —  27°  45'.  A 
fine  red  star  ;  mag.,  3^.  It  is  ij°  from  €  on  a  line  to  tf. 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  IOQ 

— .  R.  A.  (1870),  yh.  i7m.  395.  ;  Dec.,  -  25°  30.8'. 
An  intense  fiery  red  star  ;  mag.,  7.  A  line  from  Bella- 
trix  through  Sirius  and  13°  on  will  come  within  40'  S.E. 
of  it. 

41  M.  (H.  1454.)  R.  A.,  6h.  42m.  135.  ;  Dec.,  —  20° 
37.8'.  A  scattered  cluster  in  5  groups,  the  central  one 
the  richest.  A  splendid  object.  It  is  4°  almost  due  S.  of 
Sirius,  a  little  to  the  E. 

578   Dun.     (H.    1463.)     R.   A.,    6h.   45m.  55.  ;     Dec., 

—  35°  52-9  •     A  globular  cluster  brightening  towards  the 
centre.     Line  from  Bellatrix  through  Mirzam,  and  21°  on. 

12  W  VII.     (H.   1512.)     R.  A.,  yh.  i2m.  515.  ;  Dec., 

—  15°  26.5'.     A  tolerably  compressed  but  extensive  clus- 
ter.    It  is  a  singular  group  of  very  lucid  stars,  nearly  all 
of  mag.  10.     The  most  compressed  part  occupies  about 
one-third  of  the  field  with  a  power  of  66.     Line  from  a 
Tauri  through  Bellatrix  to  a  point  y|°  W.N.W.  of  Sirius. 

17  I£  VII.  (H.  1513.)  R.A.,  7h.  i4m.  285.;  Dec.,- 24° 
45.2'.  A  beautiful  cluster  of  slightly  elongated  form, 
consisting  of  a  rich  gathering  of  minute  stars  surrounding  a 
bright  white  6th  mag.  star.  Line  from  8,  Orionis  through 
Sirius  and  12°  on. 

CANIS  MINOR  (THE  LESSER  DOG). 

A  small  constellation,  of  which  the  principal  interest 
centres  in  its  lucida.  Mean  R.  A.,  7h.  2ym. ;  Dec.,  +  7°  ; 
stars,  55. 

a.  (Procyon.)  R.  A.,  7h.  33m.  335.;  Dec.,  +  5°  30.5'. 
A  famous  and  beautiful  star  of  mag.  i-J-,  although  it  cer- 
tainly deserves,  in  the  opinion  of  many  astronomers,  to 
be  rated  higher.  It  has  several  companions,  all  of  which 
are  beyond  the  reach  of  a  small  telescope. 


110          THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

ft.  (Gomelza.)  R.  A.,  ;h.  2im.  us.;  Dec.,  +  8°  30.6'. 
A  wide  though  difficult  triple.  A  3,  white  ;  B  12, 
orange  ;  C  10,  flushed.  C  itself  is  coarsely  double,  having 
a  10  mag.  companion.  D.,  AB  122.3",  AC  138.8". 

5.  R.  A.,  yh.  26m.  455.;  Dec.,  +  8°  33.2'.     A  fiery  red 
star,  varying  from  7^  to  less  than  12  mag.     i-J  E.  of  j3. 

14.  R.  A.,  yh.  52m.  393.;  Dec.,  -}-  2°  31'.  A  wide 
triple.  A  6,  pale  white  ;  B  8,  bluish  ;  C  9,  blue.  D.,  AB 
75",  AC  115".  Line  from  y  Geminorum  through  Pro- 
cyon  and  4^°  on. 

CAPRICORNUS  (THE  GOAT). 

A  zodiacal  constellation,  rather  dull  to  the  naked  eye, 
but  of  importance  astronomically.  Mean  R.  A.,  2oh.  4om. ; 
Dec.,  —  1 8° ;  stars,  154. 

a.  (Giedi.)  R.  A.,  2oh.  nm.  575.;  Dec.,  —  16°  53.1'. 
A  remarkable  multiple  object,  a1  and  o?  are  376.1"  apart. 
a1  is  composed  of  four  stars,  of  magnitudes  3,  n,  n,  and 
9^  ;  o?  of  three,  of  magnitudes  4,  9,  and  14.  A  small 
telescope  will  probably  not  show  more  than  four  stars  in 
the  entire  group. 

ft.  (Dabih.)  R.  A.,  2oh.  1401.  505.;  Dec.,  —  15°  7.8'. 
A  wide  pair  of  stars.  A  3^,  orange  yellow  ;  B  7,  sky  blue. 
D.,  205". 

oa.  R.  A.,  2oh.  23m.  365.;  Dec.,  —  18°  56.7'.  A  fine 
double.  A  6,  B  7,  both  bluish.  D.,  22.1".  It  is  2^°  E.  a 
little  south  from  a  group  of  5th  mag.  stars,  4°  from  ft  on 
a  line  from  a. 

6.  R.  A.,   2oh.   i3m.   35.;   Dec.,  —  19°  27.8'.     A  star 
with  telescopic  companion.     A  5^,  yellow  ;  B   10,  violet. 
D.,  54.1".     Line  from  d  \Q  S.  of  6  and  11^°  on. 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  Ill 

545  Birm.  R.  A.,  2oh.  lorn.  405.;  Dec.,  —  21°  39.3'.  A 
lovely  red  star,  probably  variable,  as  the  estimates  of  its 
magnitude  vary  from  6  to  y|.  Sir  J.  Herschel  says  of  it, 
"  Pure  ruby,  perhaps  the  finest  of  my  ruby  stars."  It  is 
8°  40'  almost  due  S.  of  a,  and  almost  exactly  three  times 
as  far  from  a  as  f3  is. 

312  P.  XX.  R.  A.,  zoh.  43m.  305.;  Dec.,  —  27°  46.4'. 
A  beautiful  double.  A  ;|,  pale  yellow;  B  8-J,  blue. 
D.,  18.7".  It  is  S.  and  a  little  W.  from  GO,  a  4th.  mag. 
star  which  is  the  southernmost  of  two  4th  mag.  stars,  2^° 
apart,  about  14°  S.  E.  of  a. 

72  M.     (H.  4608.)     R.  A.,  2oh.  47m.  245. ;  Dec.,  —  12° 
56.6'.     A  globular  cluster  of  very  minute  stars,  about  1.53' 
in  diameter.     Line  from  a  Aquarii  through  ft  Aquarii 
and  nearly  12°  on. 

73  M.     (H.  4617.)     R.  A.,  2oh.  52m.  555.;  Dec.,  -  13° 
3.6'.     A  rather  poor  field,  which  Smyth  records  out  of  re- 
gard to  Messier's  memory.     It  exhibits  little  compression. 
It  follows  the  last  object  by  about  5m.  of  R.  A.,  and  7' 
southward. 

30  M.  (H.  4687.)  R.  A.,  2ih.  34m.  75.;  Dec.,  -  23°  39'. 
A  fine  pale  white  cluster,  nebulous  in  small  telescope.  It 
is  somewhat  elliptical,  and  brightens  to  a  blaze  in  the  cen- 
tre. A  line  from  /?  to  2,  and  4°  on  will  reach  a  point  less 
than  i°  S.  of  it. 

CASSIOPEA. 

A  superb  constellation,  one  of  the  richest  in  the 
heavens.  Mean  R.  A.,  oh.  55m.;  Dec.,  +  60°  ;  stars,  134. 

a.  (Shedir.)  R.  A.,  oh.  34m.  i6s.;  Dec.,  +  55°  56.3'. 
A  beautiful  double,  A  3,  pale  rose  ;  B  p-J,  smalt  blue. 


112  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

D.,  62.5".  A  is  considered  variable  by  some  astrono- 
mers. 

ft.  (Caph.)  R.  A.,  oh.  3m.  i8s.;  Dec.,  +  58°  32.6'. 
A  star  with  a  distant  companion.  A  2^,  whitish  ;  B  n£, 
dusky.  D.,  297".  Very  difficult  with  a  small  tele- 
scope. 

y.  R.  A.,  oh.  5om.  45.;  Dec.,  +  60°  7.2'.  A  beautiful 
brilliant  white  3d  mag.  star,  with  others  in  field. 

rf.  R.  A.,  oh.  42m.  265.;  Dec.,  +  57°  13.9'.  A  superb 
binary  star.  A  4,  B  y-j-.  D.,  5.7",  and  decreasing..  The 
estimates  as  to  the  colors  of  the  components  differ  con- 
siderably ;  Smyth  giving  them  as  pale  white  and  purple, 
and  no  less  than  six  other  colors  being  assigned  to  them 
by  different  observers.  The  latest  estimate  is  yellow  and 
red. 

R.  R.  A.,  23h.  52m.  495.;  Dec.,  +  50°  46.4'.  A  vivid 
red  star  with  a  minute  blue  companion  20"  distant.  It 
varies  in  426  days  from  mag.  5  to  below  mag.  12.  Line 
from  6  through  a  and  8°  on. 

4.  R.  A.,  23h.  i9m.  575.;  Dec.,  +  61°  40.7'.  A  double 
star  in  a  small  telescope  ;  in  a  larger  one,  quadruple.  A  5, 
pale  yellow  ;  B  9,  yellowish.  D.,  98.1".  2°  due  N.  of  /?. 

9.  R.  A.,  23h.  58m.  335.;  Dec.,  +  61°  40.5'.  A  pair 
of  stars  ;  in  a  large  telescope,  a  group  of  four.  A  6, 
white  ;  B  8,  deep  yellow.  D.,  244".  2°  E.  and  somewhat 
N.  from  y. 

i  Birm.  R.  A.,  oh.  3m.  385.;  Dec.,  +  63°  20.4'.  A  fine 
ruby  star.  Mag.,  8-J-.  About  ij°  due  N.  of  /?. 

163  2.  R.  A.,  ih.  43m.  175.;  Dec.,  +  64°  18.1'.  An 
exquisite  double.  A  6J,  golden  red  ;  B  9,  blue.  D., 
34.9".  9°  from  B  on  line  to  Polaris. 

101  P.  XXIII.  R.  A.,  23h.  24m.  565.  ;  Dec.,  +  57° 
56.6'.  A  remarkable  multiple  star,  which,  however,  our 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  11$ 

observer  will  only  see  double.  A  5,  light  yellow ;  B  7^, 
white.  Line  from  6  to  y  and  12°  on. 

3053  2.  R.  A.,  23h.  56m.  575.;  Dec.,  +  65°  29'.  A 
beautiful  double.  A  6,  very  yellow;  B  8,  blue.  D.,  15". 
Line  from  y  Andromedae  to  y  Cassiopeae  and  8°  on. 

159  J£[  I.  (H.  158.)  R.  A.,  oh.  45m.  503.;  Dec.,  +  46° 
57.9'.  An  "almost  planetary"  nebula,  20"  in  diameter. 
Line  from  Polaris  to  ft  and  u^°  on. 

103  M,  (H.  341.)  R.  A.,  ih.  25m.  565.;  Dec.,  +  60° 
7.1'.  A  brilliant  and  beautiful  fan-shaped  cluster.  About 
i  J°  E.  and  a  little  N.  of  d. 

31  ]£  VI.  (H.  392.)  R.  A.,  ih.  38m.  395.;  Dec.,  +  60° 
41.3'.  An  elegant,  irregular  cluster.  About  2°  from  last 
object  on  line  from  6. 

30  W  VI.  (H.  5031.)  R.  A.,  23h.  5im.  355.;  Dec., 
+  56°  6.2'.  A  splendid  galaxy  cluster  of  minute  stars  ; 
"  a  very  glorious  assemblage  both  in  extent  and  richness  ; 
a  mere  condensed  patch  in  a  region  of  inexpressible 
splendor,  spreading  over  many  fields."  Discovered  by 
Miss  Caroline  Herschel.  It  is  2^°  from  ft  on  a  line 
towards  Algol. 

CENTAURUS  (THE  CENTAUR). 

A  large  constellation,  most  of  which  is  below  the  hori- 
zon in  our  latitudes,  or  so  near  it  as  to  offer  little  oppor- 
tunity for  its  study.  Mean  R.  A.,  13!!.  3501.;  Dec.,  —  50°. 
It  presents  to  us  but  one  object  of  interest. 

83  M.     (H.  3606.)     R.  A.,  i3h.  3om.  495.;  Dec.,  -  29° 
1 8.8'.     A  large  and  bright  nebula,  nucleated   in  centre. 
In  a  large  telescope  it  appears  as  a  3-branched  spiral. 
Line  from  rj  Virginis  to  y  Hydrae  and  8°  on. 
8 


114          THE    AMATEUR    TELESCOPISl's    HANDBOOK. 


CEPHEUS. 

A  highly  interesting  northern  constellation,  although  of 
little  brilliancy  to  the  naked  eye.  Mean  R.  A.,  22h.; 
Dec.,  +  73° ;  stars>  294- 

a.  (Alderamin.)  R.  A.,  2ih.  15111.  565.;  Dec.,  +  62° 
7.1'.  A  star  with  a  difficult  distant  companion.  A  3, 
white  ;  B  10,  pale  blue.  D.,  208.9". 

ft.  (Alphirk.)  R.  A.,  2ih.  27m.  145.;  Dec.,  +  70°  4.6'. 
A  beautiful  double.  A  3,  white  ;  B  8,  blue.  D.,  13.3". 

d.  R.  A.,  22h.  25m.  55.;  Dec.,  +  57°  51.1'.  A  lovely 
though  wide  double.  A  4^,  orange  tint  ;  B  7,  fine  blue, 
the  colors  well  contrasted.  A  is  variable  from  mag.  3^  to 
4^.  Its  interval  from  maximum  to  minimum  is  3d.  19!!., 
and  from  minimum  to  maximum  id.  i4h.  D.,  19.3". 

H.  R.  A.,  2oh.  i2m.  355.;  Dec.,  +  77°  22.7'.  A  neat 
double.  A  4^,  bright  white  ;  B  8-J-,  smalt  blue.  A  fine 
object.  D.,  7.2".  A  line  drawn  from  y  Androm.  through 
d  Cassiopese  to  within  12°  of  Polaris  will  find  this  star. 

//.  R.  A.,  2ih.  4om.  8s.;  Dec.,  +  58°  16.5'.  A  richly 
colored  star  with  two  companions.  It  varies  from  mag.  4 
to  6.  Sir  W.  Herschel  says  :  "  It  is  of  a  very  fine  deep 
garnet  color,  .  .  .  and  a  most  beautiful  object,  espe- 
cially if  we  look  for  some  time  at  a  white  star  before  we 
turn  our  telescope  to  it,  such  as  #,  which  is  near  at  hand." 
It  is  5°  from  or  on  a  line  towards  /3  Pegasi. 

£.  R.  A.,  22h.  om.  355.;  Dec.,  +  64°  5. 4'.  A  splendid 
double.  A  5,  B  7,  both  blue.  D.,  6.6".  It  is  7°  from  /? 
on  line  towards  d. 

248  P.  XXI.  R.  A.,  2ih.  35m.  375.;  Dec.,  +  56°  59-5'- 
A  neat  triple.  A  6,  pale  yellow ;  B  and  C  both  8-J-,  both 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  115 

gray.  D.,  AB  11.7",  AC  19.8".  A  line  from  Polaris 
through  /?  and  13°  on  will  pass  within  ^°  W.  of  this 
star. 

256  P.  XXI.  R.  A.,  2ih.  36m.  573.;  Dec.,  +  57°  5'. 
A  very  neat  double.  A  8,  white  ;  B  9,  pale  violet.  D., 
12.6".  Line  from  y  Cassiopeae  through  /?  Cassiopeae  and 
3°  on. 

147  B.  R.  A.,  2ih.  4801.  175.;  Dec.,  +  55°  16.8'.  A 
pretty  double.  A  6,  greenish  white  ;  B  7^,  bluish  white. 
D.,  20. i".  Line  from  y  Cygni  to  a  Cygni  and  16° 
on. 

2893  2.  R.  A.,  22h.  lom.  545.;  Dec.,  +  72°  45.8'.  A 
fine  double.  A  6,  yellowish;  B  8,  white.  D.,  28.8". 
About  midway  between  /3  and  y. 

U.  R.  A.,  oh.  52m.  335.;  Dec.,  -f  81°  17'.  Ceraski's 
2d  variable,  the  most  rapid  yet  known.  It  varies  from 
mag.  7  to  9,  and  its  periods  of 
maximum,  minimum,  and  change 
are  2  hours  each.  According  to 
Knott,  it  is  bluish  at  maximum 
and  ruddy  at  minimum.  I  ap- 
pend a  diagram  (from  Webb) 
which  will  assist  in  finding  this 
star. 

42  W  VI.    (H.  4590.)    R.  A., 
2oh.  29m.  175.;  Dec.,  +  60°  16.3'. 
FlG'  I3'  A    large    and    rich    cluster    of 

minute  stars.     2°  from  ?/  on  line  from  e  Cassiopeae. 

52  M.  (H.  4957.)  R.  A.,  23h.  19111.  2is.;  Dec.,  +  60° 
59.5'.  An  irregular  cluster,  nebulous  in  a  small  telescope, 
but  showing  some  stars.  It  is  of  a  somewhat  triangular 
form,  with  an  orange -tinted  8th  mag.  star  at  one  angle. 
At  £  the  distance  between  ft  Cassiopeae  and  a  Cephei. 


Il6  THE    AMATEUR    TELESCOPIST'S   HANDBOOK. 


CETUS  (THE  WHALE). 

The  largest  of  all  the  constellations.  Mean  R.  A., 
ih,  35m.;  Dec.,  —  18°;  stars,  301. 

a.  (Menkab.)  R.  A.,  2h.  56m.  315.;  Dec.,  +  3°  39.5'. 
A  star  with  a  distant  companion.  A  2-J-,  bright  orange  ; 
B  10,  pale  gray.  Diff.  of  R.  A.,  29.6".  A  fine  blue  5th 
mag.  star  in  field  towards  N. 

q.  R.  A.,  ih.  3m.  35.;  Dec.,  —  10°  45.9'.  A  probably 
variable  star  with  distant  companion.  A  3^,  yellow  ;  B 
10,  lead  color.  D.,  2.25". 

2.  R.  A.,  ih.  46m.  25.;  Dec.,  —  io°52.8'.  A  3^,  topaz 
yellow  ;  B  9,  white.  D.,  185". 

o.  (Mira.)  R.  A.,  2h.  i3m.  475.;  Dec.,  —  3°  28.7'.  A 
wonderful  variable.  It  changes  from  mag.  2  to  invisi- 
bility, according  to  Smyth  ;  from  mag1.  2  to  mag.  10,  ac- 
cording to  Webb ;  and  from  mag.  1.7  to  mag.  8  or  9  on 
Struve's  scale,  according  to  Schonfeld.  Its  period  is 
33 id.  8h.  14111.  i6s.,  according  to  Argelander.  Mira  is 
about  half-way  between  y  and  2,. 

26.  R.  A.,  oh.  58m.  95. ;  Dec.,  +  o°  46.6'.  A  neat  dou- 
ble. A  6J,  pale  topaz  ;  B  9^,  lilac  tint.  D.,  16".  Mid- 
way between  y  Pegasi  and  £  Ceti. 

37.  R.  A.,  ih.  8m.  515.  ;  Dec.,  —  8°  30.7'.  A  fine  though 
wide  quadruple.  A  6,  white  ;  B  7^,  light  blue  ;  C  8, 
yellow  ;  D  TO,  violet.  D.,  AB  48.3",  CD  20.5".  It  is 
2^°  almost  due  E.  of  0,  and  2°  40'  N.  N.  W.  of  rj. 

66.  R.  A.,  2h.  7m.  8s. ;  Dec.,  —  2°  54.3'.  A  beautiful 
double.  A  7,  pale  yellow ;  B  8-J,  sapphire  blue.  D., 
15.35".  It  is  i°  40'  W.  and  a  little  N.  from  Mira. 

113  P.  O.     R.  A.,  oh.  28m.  525.;  Dec.,  —  9°  5.3'.     A 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  1 17 

fine  double.  A  7,  cream  yellow  ;  B  9,  smalt  blue ;  D., 
19.9".  10°  from  ft  on  line  towards  y  Pegasi. 

146  P.  O.  R.  A.,  oh.  35m.  6s.  ;  Dec.,  -  4°  57.3'.  A 
beautiful  though  wide  double.  A  6^,  pale  topaz  ;  B  9, 
violet  tint.  D.,  65".  Line  from  rj  to  a  Pegasi ;  the  star 
will  be  found  9°  from  the  former. 

191  P.  I.  R.  A.,  ih.  46m.  us.;  Dec.,  +  10°  16".  A 
beautiful  close  double.  A  y-J,  B  8,  both  lucid  white.  It  is 
13°  from  a  Arietis  (to  which  constellation  it  really  be- 
longs) on  a  line  to  6  Ceti.  D.,  3.6". 

150  2.  R.  A.,  ih.  37m.  ;  Dec.,  —  7°  42'.  A  beautiful 
double.  A  8,  B  8J,  both  very  white.  D.,  36.2".  Line 
from  i  through  6  and  5°  on  will  reach  a  point  40'  S.  of  it. 

23  I£  IV.  (H.  544.)  R.  A.,  2h.  2im.  575.  ;  Dec.,  -  i° 
38'.  A  planetary  nebula,  bluish  white,  pale  but  very  dis- 
tinct. 7°  from  y  on  line  towards  2,. 

77  M.  (H.  600.)  R.  A.,  2h.  37m.  35.  ;  Dec.,  —  o°  28.3'. 
A  small  bright  round  stellar  nebula.  It  is  3^°  due  S. 
of  y. 

CLYPEUS  SOBIESKI  (SOBIESKI'S  SHIELD). 

A  small  modern  constellation  in  the  most  brilliant  por- 
tion of  the  Milky  Way.  Mean  R.  A.,  i8h.  23m.  ;  Dec., 


24  M.  (H.  4397.)  R.  A.,  i8h.  nm.  445. ;  Dec.,  —  18° 
26.8'.  A  superb  field  of  small  stars,  nebulous  in  a  small 
telescope.  It  really  belongs  to  Sagittarius,  and  is  3° 
N.  N.  W.  from  jj.  Sag.  Line  from  Altair  to  A  Antinoi, 
and  as  far  again. 

16  M.  (H.  4400.)  R.  A.,  i8h.  i2m.  345.  ;  Dec.,  —  13° 
49.7'.  A  scattered  but  fine  large  stellar  cluster.  Line 
from  y  Sagittarii  to  /A  Sag.  and  7°  on. 


Il8  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

18  M.  (H.  4401.)  R.  A.,  i8h.  13111.  305. ;  Dec.,  -  17° 
10.8'.  A  somewhat  long  and  straggling  cluster  of  minute 
stars.  It  lies  4°  from  ,w  Sagittarii  on  a  line  towards  f 
Aquilae.  Webb  calls  it  a  glorious  field  in  very  rich  vicin- 
ity, and  adds,  "  South  of  it  lies  a  region  of  surpassing 
splendor."  (About  i°.) 

17  M.  (H.  4403.)  R.  A.,  i8h.  i4m.  i6s. ;  Dec.,  —  16° 
14.9'.  The  singular  and  beautiful  Horse-shoe  or  Omega 
nebula,  "  a  magnificent  arched  and  irresolvable  lumi- 
nosity," in  a  splendid  field.  It  is  pronounced  gaseous  by 
Huggins.  It  is  4^°  from  jn  Sag.  on  line  towards  e  Aqui- 
te  -  y  N.  by  E.  from  18  M. 

26  M.  (H.  4432.)  R.  A.,  i8h.  39m.  us.;  Dec.,  —  9° 
30.6'.  A  small  and  coarse  but  bright  cluster.  Line  from 
ft  Herculis  through  /3  Ophiuci  and  20^°  on. 

COMA  BERENICES  (BERENICE'S  HAIR). 

A  constellation  distinguished  by  the  beautiful  diffused 
cluster  which  forms  its  principal  part.  Mean  R.  A.,  i2h. 
3om.;  Dec.,  +  27°;  stars,  117. 

24.  R.  A.,  i2h.  29m.  365.;  Dec.,  —  18°  58.9'.  A 
beautiful  double.  A  5^,  orange ;  B  7,  emerald  tint,  the 
colors  very  brilliant.  D.,  20".  A  little  less  than  13° 
from  ft  Leonis  on  line  towards  Arcturus. 

202  P.  XII.  R.  A.,  i2h.  46m.  295.;  Dec.,  +  20°  46.2'. 
A  neat  double.  A  ;|,  B  8,  both  white.  D.,  15.7".  Line 
from  Spica  through  e  Virginis  and  9^°  on. 

92  lp  I.  (H.  3101.)  R.  A.,  i2h.  3om.  295.;  Dec., 
+  28°  33-9'-  A  large  club-shaped  nebula,  brightening 
towards  the  centre.  It  is  2^°  from  15,  a  4th  mag.  star 
(the  largest  in  the  cluster)  in  the  extreme  north  of  the 
Tresses,  on  a  line  towards  Arcturus. 


THE    AMATEUR    TELESCOPIST*S   HANDBOOK.  119 

24  }$  V.  (H.  3106.)  R.  A.,  i2h.  3om.  505.;  Dec., 
+  26°  35.7'.  A  curious  "  streak  "  of  nebulosity,  shaped 
somewhat  like  a  weaver's  shuttle,  and  15'  in  length.  It 
will  be  found  difficult  with  anything  under  4  inches.  It 
lies  just  outside  the  Tresses,  or  principal  cluster,  to  the  E. 

53  M.  (H.  3453.)  R.  A.,  i3h.  ym.  305.;  Dec.,  +  18° 
45 -3'-  A  globular  cluster  of  minute  stars  of  mag.  11-15. 
"A  ball  of  innumerable  worlds."  Line  from  Polaris 
through  43,  the  easternmost  of  the  only  two  4th  mag. 
stars  in  the  asterism,  and  9^°  on. 

64  M.  (H.  3321.)  R.  A.,  i2h.  5im.  195.;  Dec.,  +  22° 
16.9'.  A  fine  nebula,  but  difficult  with  small  apertures. 
Bright  nucleus.  Line  from  Spica  through  £  Virginis  and 
11°  on;  then  ij°  due  E. 


CORONA  BOREALIS  (THE  NORTHERN  CROWN). 

A  beautiful  little  constellation.  Mean  R.  A.,  i5h.  35m.; 
Dec.,  +  28°;  stars,  87. 

a.  (Alphecca,  or  Gemma.)  R.  A.,  15!!.  3om.  25.;  Dec., 
+  27°  5.1'.  A  beautiful  star  with  a  distant  companion. 
A  2,  brilliant  white  ;  B  8,  pale  violet.  Difference  of  R. 
A.,  1 1. 6s. 

8>.  R.  A.,  i5h.  35m.  145.;  Dec.,  +  36°  59.7'.  A  beautiful 
double.  A  5,  bluish  white  ;  B  6,  smalt  blue.  D.,  6.3". 
Line  from  e  Bootis  through  d  Bootis  and  6°  on. 

v.  R.  A.,  i6h.  i2m.  205.;  Dec.,  +  29°  27.5'.  A  quad- 
ruple, but  a  small  aperture  will  hardly  show  it  more  than 
double.  A  6,  B  10,  C  9.  D.,  AB  86.4",  AC  123.3".  12° 
from  /?  Herculis  on  line  towards  /3  Bootis. 

T.  R.  A.,  i5h.  54m.  535.;  Dec.,  +  26°  14'.  The  fa- 
mous "Blaze  star"  which  in  May,  1866,  suddenly  grew 


120  THE    AMATEUR    TELESCOPIST'S   HANDBOOK. 

from  a  gih  magnitude  star  to  a  2d  magnitude  one.  Prob- 
ably a  long-period  variable.  It  is  now  of  the  pth  magni- 
tude, a,  y,  and  6  form  a  line  which,  prolonged  2^-  de- 
grees beyond  d,  will  reach  a  point  about  £°  due  S.  of  T. 

CORVUS  (THE  CROW). 

A  small  and  not  very  important  constellation.  Mean 
R.  A.,  i2h.  1 5m.;  Dec.,  —  18°  ;  stars,  61. 

ft.  R.  A.,  i2h.  28m.  365.;  Dec.,  —  22°  47.3'.  A  fine 
star  with  two  distant  companions.  A  2^,  ruddy  yellow  ;  B 
7,  greenish  yellow  ;  C  8,  dull  gray.  Difference  of  R.  A., 
AB  27.45.;  AC  285. 

#.  R.  A.,  i2h.  24m.  us.;  Dec.,  —  15°  54.1'.  A  fine 
double.  A  3,  pale  yellow  ;  B  8J,  purple.  D.,  22.9". 

CRATER  (THE  CUP). 

A  diminutive  constellation,  but,  like  Corvus,  one  of  the 
original  48.  Mean  R.  A.,  nh.  1501.;  Dec.,  —  18°  ;  stars 
95- 

a.  (Alkes.)  R.  A.,  loh.  54m.  275.;  Dec.,  —  17°  42.9'. 
A  fine  star,  notable  for  its  two  beautiful  companions  in 
the  field.  A  4,  orange  tint ;  B  8,  intense  blood  color ; 
C  9,  pale  blue.  B  is  the  lovely  star  next  described. 

R.  R.  A.,  loh.  55m.  8s.;  Dec.,  —  14°  29.4'.  A  beau- 
tiful crimson  or  scarlet  star,  varying  from  mag.  8  to  9. 
Its  color  seems  to  be  growing  paler. 

17.  R.  A.,  nh.  26m.  495.;  Dec.,  —  28°  39.6'.  A  neat 
double.  A  5^,  lucid  white  ;  B  7,  violet  tint.  D.,  8.7". 
Line  from  Spica  J°  under  e  Corvi  and  about  11°  on. 


THE   AMATEUR    TELESCOPIST's    HANDBOOK.  121 


CYGNUS  (THE  SWAN). 

A  superb  constellation,  one  of  the  finest  in  the  northern 
heavens.  Mean  R.  A.,  2oh.  17111. ;  Dec.,  +  41°;  stars, 
360. 

a.     (Deneb.)     R.  A.,  2oh.  37m.  403.;  Dec.,  +  44°  53.2'. 

A  beautiful  brilliant  white  star.  It  has  a  distant  com- 
panion of  mag.  12^,  which  is  beyond  the  powers  of  a  small 
telescope. 

ft.  (Albireo.)  R.  A.,  igh.  26m.  175.;  Dec.,+  27°  43.7'. 
A  lovely  double,  one  of  the  finest  in  the  skies.  A  3,  topaz 
yellow  ;  B  7,  sapphire  blue,  the  colors  in  beautiful  con- 
trast. D.,  34.8". 

//.  R.  A.,  2ih.  3901.  i2s.;  Dec.,  +  28°  15'.  A  beauti- 
ful double  with  a  distant  companion.  A  5,  white ;  B  6,  C 
7j,  both  blue.  D.,  AB  3.84",  AC  208.74".  Distance 
AB  is  decreasing.  A  line  from  s  Cassiopeae  through  ft 
Cass.,  and  32°  on,  will  reach  it  at  a  point  19°  due  N.  of  e 
Pegasi. 

o2.  R.  A.,  2oh.  lorn.  ios.;  Dec.,  +  46°  24.5'.  A  wide 
triple  in  a  small  telescope,  quadruple  in  anything  over  5 
inches.  A  4,  orange  ;  B  7^,  C  5^,  both  cerulean  blue. 
D.,  AB  106.8",  AC  337.8".  C  is  o1  Cygni.  This  group  is 
5°  from  Deneb,  on  a  line  to  y  Draconis. 

X*.  R.  A.,  i9h.  44m.  385.;  Dec.,  +  33°  9-7'-  An  ex- 
traordinary variable,  with  distant  companion.  It  is  of  a 
splendid  red  color,  and  varies  from  mag.  5  (4,  according 
to  some  observers)  to  invisibility  in  4o6d.  It  takes  about 
3^  months  in  increasing  from  minimum  to  maximum 
brightness,  and  the  same  time  in  decreasing  ;  after  which 
it  remains  invisible  for  about  six  months.  It  is  8°  from  ft 
on  a  line  to  v. 


122          THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

X1.  R.  A.,  iph.  42111.  155.;  Dec.,  +  33°  28.8'.  A  fine 
double.  A  5,  golden  yellow;  B  9,  pale  blue.  D.,  25.7". 
It  is  but  2m.  235.  W.  of  the  above  object,  and  9.1'  nearer 
the  N. 

16.  R.  A.,  iph.  38m.  545.;  Dec.,  4- 50°  16.2'.  A  fine 
double.  A  6J,  B  7,  both  fawn-color.  D.,  37.9".  It  is 
ij°  from  z  on  line  to  a. 

61.  R.  A.,  2ih.  im.  575.;  Dec.,  +  38°  12.5'.  A  famous 
and  most  interesting  double,  perhaps  a  binary.  A  5  J,  B  6, 
both  yellow  ;  the  smaller  one  of  deeper  tint.  D.,  20.1". 
This  was  the  first  star  the  distance  of  which  was  deter- 
mined. This  was  accomplished  in  1838,  by  the  illustri- 
ous Bessel  of  Konigsberg.  He  ascertained  its  parallax  to 
be  0.3 136".  A  more  recent  determination  is  that  of 
Auwers — 0.56  ;  and  there  is  but  one  star  which  exhibits 
a  larger  parallax,  namely,  a  Centauri.  The  distance  of 
6 1  Cygni  is  366,400  times  the  distance  of  the  earth  from 
the  sun,  and  its  light  occupies  six  years  in  traversing  this 
stupendous  interval.  A  line  from  Vega  through  y  Cygni 
and  10°  on,  reaches  a  point  ij-0  due  S.  of  61 ;  and  a  line 
from  a  through  v  and  prolonged  3^°  strikes  it. 

R.  R.  A.,  i9h.  33m.  525.;  Dec.,  +  49°  57'.  A  red  star, 
varying  in  425  days  from  mag.  6  to  14.  It  is  12°  from 
a  towards  y  Draconis. 

6  B.  R.  A.,  i9h.  9m.  i6s.;  Dec.,  +  49°  37.9'.  A  pretty 
double.  A  6£,  B  7,  both  yellow.  D.,  9.8".  3^°  due  S. 

Of  H. 

149  P.  XIX.  R.  A.,  i9h.  23m.  435.  ;  Dec.,  +  36° 

18.4'.  A  very  elegant  double.  A  8J,  white  ;  B  9,  pale 

blue.  D.,  7.2".  8°  from  /?  on  line  towards  H. 

276  P.  XIX.  R.  A.,  i9h.  4im.  375.;  Dec.,  +  35° 

49.4'.  A  neat  double.  A  8,  B  8J,  both  white.  D., 

14.7".  Line  from  Polaris  through  6  and  91°  on. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  123 

278  P.  XIX.  R.  A.,  iQh.  4im.  445.;  Dec.,  +  34° 
44.6'.  A  fine  double.  A  6,  straw  color ;  B  8,  smalt 
blue  ;  colors  beautiful.  D.,  38.2".  About  i°  S.  of  last 
object. 

2708  2.  R.  A.,  2oh.  34m.  305.;  Dec.,  +  38°  15.4'.  A 
double  star.  A  4*,  yellow  ;  B  pj,  blue.  D.,  24.6",  and 
increasing.  Line  from  a  Cephei  through  a  Cyg.,  and 
7°  on. 

1470  H.  R.  A.,  iph.  59m.;  Dec.,  +  38°  o'.  A  beautiful 
double.  A  8J,  pale  clear  red  ;  B  91,  intense  blue.  D., 
23.8".  A  line  from  a  to  fi  passes  about  i°  due  S.  of  it, 
ioj°  from  the  former. 

2048  h.  (H.  4511.)  R.  A.,  i9h.  37m.  255.;  Dec.,  +  39° 
56.1'.  A  rich  cluster  of  very  minute  stars  of  mag.  n  to 
15.  5°  from  d  on  line  to  /?. 

20  $[  VIII.  (H.  4559.)  R.  A.,  2oh.  7m.  223.;  Dec., 
+  26°  9.6'.  A  large  and  rich  but  loose  cluster  of  stars  from 
mag.  6  to  ii.  Line  from  j3  Cassiopese  through  y  Cyg. 
and  1 8°  on. 

8  33  VII.  (H.459I.)  R.  A.,2oh.  29m.  575.;  Dec.,  +  27° 
56.2'.  A  large,  bright  and  rich  cluster.  Line  from  e 
Cassiopese,  the  northernmost  star  of  the  Chair,  through 
€  Cyg.  and  6J°  on. 

2107  h.  (H.  4645.)  R.  A.,  2ih.  7m.  i8s. ;  Dec., 
+  45°  13.8'.  An  extended  and  pretty  rich  cluster  of  prin- 
cipally loth  mag.  stars.  Between  a  and  p,  6°  from 
former,  and  due  E. 

39  M.  (H.  4681.)  R.  A.,  2ih.  28m.  155.;  Dec.,  +  47° 
56.9'.  A  brilliant  cluster  in  a  rich  vicinity.  Line  from  /3 
through  y  and  14°  on. 

56  l^  VIII.  (H.  4575.)  R.  A.,  2oh.  19111.  95.;  Dec., 
+  40°  25.6'.  A  beautiful  group  of  stars,  mag.  10  to  12. 
It  is  £°  from  y  on  line  to  a. 


124  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 


DELPHINUS  (THE  DOLPHIN). 

A  little  constellation  which  offers  a  very  rich  region  for 
sweeping.      Mean  R.  A.,  2oh.  2om.;  Dec.,  +  12°;  stars, 


y.  R.  A.,  2oh.  4im.  335.;  Dec.,  +  15°  43.9'.  A 
beautiful  double.  A  4,  yellow  ;  B  7,  light  emerald,  but 
appears  to  vary  in  color,  since  it  is  described  as  yellow, 
green,  and  blue,  by  various  observers.  D.,  11.3".  This 
constellation  may  be  recognized  by  the  little  square  of 
stars  between  Aquila  and  Pegasus  ;  y  is  the  easternmost 
of  these. 

2703  2.  R.  A.,  2oh.  31111.  405.;  Dec.,  +  14°  21'.  A 
pretty  triple.  A  white,  B  yellowish,  C  white,  all  mag.  7^. 
D.,  AB  25.2",  AC  69.2",  BC  59.7".  This  object  is  but  9' 
N.  and  43"  W.  of  ft,  the  southernmost  and  largest  star  in 
the  square. 

DRACO  (THE  DRAGON). 

A  winding  and  convoluted  constellation,  always  above 
the  horizon.  Mean  R.  A.,  i5h.  55m.;  Dec.,  +  70°;  stars, 
255- 

a.  (Thuban.)  R.  A.,  i4h.  im.  245.;  Dec.,  +  64°  54.1'. 
A  star  with  a  distant  companion.  A  3^,  pale  yellow  ;  B  8, 
dusky.  Difference  of  R.  A.,  23.95.  This  star  is  suspected 
of  variability,  having  been  rated  as  of  magnitudes  from  2 
to  4. 

#.  R.  A.,  i9h.  1  2m.  315.;  Dec.,  +  67°  28'.  A  star  with 
a  distant  companion.  A  3,  deep  yellow  ;  B  9^,  pale  red. 
D,  IS4-7". 


THE    AMATEUR    TELESCOPIST'S   HANDBOOK.  125 

i.  R.  A.,  i5h.  22m.  295.;  Dec.,  +  59°  21.1'.  A  bright 
star  with  distant  companion.  A  3,  orange  tint ;  B  9,  pale 
yellow.  D.,  254.6".  Other  stars  in  field.  Line  from 
Polaris  through  y  Urs.  Min.  and  1 2 J°  on. 

o.  R.  A.,  i8h.  49m.  345.;  Dec.,  +  59°  15.3'.  A  neat 
double  in  a  fine  field.  A  5,  orange  yellow  ;  B  lilac.  D., 
31.8".  A  line  from  ft  Herculis  through  y  Drac.  will  pass 
within  J°  of  it,  io£°  from  the  latter. 

ip\  R.  A.,  lyh.  43m.  545.  ;  Dec.,  +  72°  12.5'.  A  neat 
double.  A  5^,  B  6,  both  pearly  white.  D.,  30.9".  8° 
from  6  on  line  to  y  Urs.  Min. 

40.  R.  A.,  i8h.  8m.  i6s.  ;  Dec.,  +  79°  59'.  A  fine 
double.  A  5^,  B  6,  both  white.  D.,  20.1".  10°  from 
Polaris  on  line  to  y. 

2278  2.  R.  A.,  i8h.  om.  585.;  Dec., +  56°  26'.  A 
triple  star.  A  7^,  B  8,  both  white  ;  C  8J.  D.,  AB  38.1", 
AC  5.9".  ij°  S.  and  a  little  E.  from  £,  the  3d  mag.  star 
6°  N.  of  y. 

190  B.  R.  A.,  i8h.  3im.  265.  ;  Dec.,  +  52°  15.7'.  A 
beautiful  double.  A  6,  very  yellow  ;  B  8-J-,  very  blue. 
Colors  very  fine.  D.,  25.4".  13°  from  Vega  on  line  to 
the  Pole. 

2573  2.  R.  A.,  i9h.  38m.  303.;  Dec.,  +  60°  15.3'. 
A  double  star.  A  6£,  white;  B  9,  blue.  D.,  18.1". 
Exactly  on  line  from  a  Lyrse  to  Polaris,  and  22°  from  the 
former. 

256  #  I.  (H.  3671.)  R.  A.,  i3h.  45™.  33*.  ;  Dec., 
+  60°  44.8'.  An  irregularly  round  nebula,  brightening 
towards  the  centre.  11°  from  rj  Urs.  Maj.  on  line  to- 
wards Polaris. 

102  M.  (H.  4064.)  R.  A.,  ish.  6m.  555. ;  Dec.,  +  57° 
25.6'.  A  small  and  rather  faint  nebula.  13°  from  77  Urs. 
Maj.  on  line  to  B,  Drac. 


126  THE   AMATEUR    TELESCOPIST'S    HANDBOOK. 

37  ]J[  IV.  (H.  4373.)  R.  A.,  i7h.  58m.  35s.  ;  Dec., 
+  66°  38'.  A  planetary  nebula.  It  will  prove  difficult  in 
a  small  telescope,  but  should  be  tried.  Like  other  plane- 
tary nebulae  it  somewhat  resembles  a  star  out  of  focus.  A 
line  from  d  to  rj  will  pass  within  less  than  i°  S.  of  it,  7° 
from  the  former. 


EQUULEUS  (THE  LITTLE  HORSE). 

A  diminutive  asterism  which  offers,  outside  of  its  good 
low-power  fields,  but  one  object  for  our  examination. 
Mean  R.  A.,  2ih.  lorn. ;  Dec.,  +  5°  ;  stars,  36. 

355,  356  P.  XX.  R.  A.,  2oh.  47m.  i8s.  ;  Dec.,  +  6° 
55'.  A  pair  of  stars,  both  mag.  8-J-,  both  white.  D., 
40.3".  15°  from  Altair  on  a  line  from  6  Pegasi. 


ERIDANUS  (THE  RIVER). 

An  extensive  southern  constellation,  a  large  proportion 
of  which  is  below  the  horizon  in  England  and  the  United 
States.  Mean  R.  A.  of  portion  visible  in  latitude  40°,  3h. 
4om. ;  Dec.,  -  25°  ;  stars,  343. 

32.  R.  A.,  3h.  48m.  465.  ;  Dec.,  -  3°  16.8'.  A  splen- 
did double.  A  5,  topaz  yellow ;  B  7,  sea-green  or  blue. 
D.,  6.7".  Secchi  calls  the  colors  magnifici,  superbi.  Line 
from  Sirius  through  Rigel,  and  19°  on. 

39.  R.  A.,  4h.  9m.  los. ;  Dec.,  —  10°  31.6'.  A  delicate 
but  not  difficult  double.  A  5,  yellow;  B  n,  deep  blue. 
D.,  6.3".  This  star  is  known  as  A  in  some  catalogues 
and  maps.  Line  from  £  Orionis  (lowest  in  belt),  through 
ft  Erid.  and  14}°  on. 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  127 

55.  R.  A.,  4h.  38m.  i8s. ;  Dec.,  -  8°  59.9'.  A  beauti- 
ful double.  Both  mag.  y-J,  both  yellowish  white.  D.,  g". 
Line  from  £  Orionis  through  ft  Erid.  and  7^°  on. 

62.  R.  A.,  4h.  5om.  595.;  Dec.,  —  5°  20.8'.  A  wide 
double.  A  6,  white  ;  B  8,  lilac.  D.,  63.8".  Line  from 
upper  part  of  Orion's  sword-cluster  through  ft  Erid.  and 
3°  on. 

/.  R.  A.,  3h.  44m.  335.;  Dec.,  —  37°  57.8'.  A  superb 
double.  A  5,  B  5^.  D.,  8.5".  Line  from  upper  part  of 
Orion's  sword-cluster  through  Rigel  and  50°  on. 

2569  h.  (H.  748.)  R.  A.,  3h.  34m.  205.;  Dec.,  -  35° 
48.9'.  A  globular  cluster,  nebulous  in  small  telescope.  A 
line  from  6  Orionis  through  ft  Erid.  and  52°  on  will  pass 
within  2°  E.  of  this  cluster. 

26  ]£  IV.  (H.  826.)  R.  A.,  4h.  9m.  ios.;  Dec.,  —  13° 
1.3'.  A  planetary  nebula,  very  faint  in  small  telescope, 
and  not  bearing  high  powers.  Lassell  pronounces  it  the 
most  interesting  and  extraordinary  object  of  the  kind 
which  he  had  ever  seen.  Line  from  s  Orionis  to  ft  Erid. 
and  15°  on.  It  is  4^°  from  y»  E.  and  a  little  N. 

GEMINI  (THE  TWINS). 

A  highly  interesting  and  important  constellation.  Mean 
R.  A.,  7h.;  Dec.,  +  22°  ;  stars,  190. 

a.  (Castor.)  R.  A.,  yh.  27m.  353.;  Dec.,  +  32°  7.8'. 
A  splendid  binary  star,  the  largest  and  finest  in  the  north- 
ern hemisphere.  A  3,  bright  white  ;  B  3^,  pale  white. 
D.,  5.64".  The  period  of  revolution  of  this  magnificent 
system  is,  according  to  Thiele,  996  years. 

ft.  (Pollux.)  R.  A.,  7h.  38m.  355.;  Dec.,  +  28°  17.5'. 
A  multiple  star  of  6  components.  Our  observer  will  see 


123  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

it  as  a  coarse  triple.  A  2,  orange  tinge  ;  D  9^  ;  E  9.  D., 
AD  206.3",  AE  229.2". 

y.  R.  A.,  6h.  3im.  2is.;  Dec.,  +  16°  29.5'.  A  bright 
white  star  of  mag.  3,  in  a  beautiful  field. 

e.  R.  A.,  6h.  3701.  ios.;  Dec.,  +  25°  14.3'.  A  star  with 
distant  companion.  A  3,  yellow  ;  B  9^,  cerulean  blue. 
D.,  1 10.6".  Rather  difficult. 

K.  R.  A.,  yh.  37m.  485.;  Dec.,  +  24°  39.7'.  A  very 
delicate  and  beautiful  but  difficult  double.  A  4,  orange  ; 
B  10,  pale  blue.  D.,  6.39".  4°  due  S.  of  Pollux. 

R.  R.  A.,  7h.  om.;  Dec.,  +  22°  53'.  An  extraordinary 
variable,  from  6^  to  12^  mag.  Period  371  days.  Ac- 
cording to  Hind,  this  star  is  blue,  red,  and  yellow,  by 
turns.  It  yielded  to  Secchi  a  wonderful  spectrum  with 
bright  lines.  10°  from  Pollux  on  line  to  y. 

15.  R.  A.,  6h.  2im.  135.;  Dec., -f- 20°  51.5'.  A  fine 
double.  A  6,  flushed  white  ;  B  8,  bluish.  D.,  31".  5° 
from  y  on  line  to  yu. 

20.  R.  A.,  6h.  25m.  528.;  Dec.,  +  17°  51.4'.  A  beau- 
tiful double  in  a  fine  field.  A  8,  topaz  yellow  ;  B  8^, 
cerulean  blue.  D.,  20".  2°  from  y  on  a  line  to  77. 

38.  R.  A.,  6h.  48m.  ^265.;  Dec.,  +  13°  19.1'.  A  very 
fine  double.  A  5^,  light  yellow ;  B  8,  purple  ;  colors 
very  marked.  D.,  6.3".  5^°  from  y  on  line  to  Procyon. 

135  Birm.  R.  A.,  6h.  4m.  35.;  Dec.,  -j-  26°  2.3'.  A 
fine  ruby  star  of  mag.  7j  or  8.  Line  from  y  i°  W.  of  //, 
and  5°  further. 

540  South.  R.  A.,  7h.  2im.  6s.;  Dec.,  +  22°  22.2'. 
A  beautiful  pair.  A  7^,  red  ;  B  9,  blue.  D.,  35.6".  2° 
due  E.  of  d. 

1108  2.  R.  A.,  yh.  26m.  155.  ;  Dec.,  +  23°  7.8".  A 
beautiful  double.  A  7,  yellowish  white ;  B  9,  bluish. 
D.,  11.5".  Line  from  y  to  d  and  3°  on. 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  I2Q 

1035  2.  R.  A.  (1880),  yh.  4m.;  Dec.,  +  22°  29'.  A 
beautiful,  double.  Both  mag.  7^,  both  yellowish.  D., 
8.5".  Line  from  y  to  £  and  2°  on. 

26  J$  VIII.  (H.  1325.)  R.  A.,  sh.  54m.  245.;  Dec., 
4-  23°  17.9'.  A  rather  large  cluster  of  40  or  50  stars  from 
mag.  8  to  15.  2j°  W.  and  a  little  N.  of  77,  is  a  5th  mag. 
star,  i.  The  cluster  is  i  J°  due  W.  of  this  star. 

35  M.  (H.  1360.)  R.  A.,  6h.  2m.  45.;  Dec.,  +  24° 
21.2'.  A  gorgeous  cluster  of  stars  from  mag.  9  to  16. 
Smyth  says  :  "  From  the  small  stars  being  inclined  to 
form  curves  of  three  or  four,  and  often  with  a  large  one 
at  the  root  of  the  curve,  it  somewhat  reminds  one  of  the 
bursting  of  a  sky-rocket."  Lassell  says  :  "  A  marvel- 
lously striking  object.  No  one  can  see  it  for  the  first 
time  without  an  exclamation.  .  .  .  Nothing  but  a 
sight  of  the  object  itself  can  convey  an  idea  of  its  exquis- 
ite beauty."  3^°  from  jw  on  line  to  ft  Tauri. 

40  $[  VIII.  (H.  1490.)  R.  A.,  7h.  om.  395.;  Dec., 
+  27°  21.7'.  A  large  scattered  cluster.  7°  from  Castor 
on  line  to  Betelgeuse. 

45  IJU  IV.  (H.  1532.)  R.  A.,  yh.  22m.  415.;  Dec., 
+  21°  8.1'.  A  star  enveloped  in  a  nebulous  atmosphere 
about  25"  in  diameter  ;  a  most  remarkable  object.  The 
central  star  is  of  mag.  7  J.  Line  from  s  to  <5  and  2°  on. 

ii  J§L  VIII.  (H.  1534.)  R.  A.,  yh.  22m.  535.;  Dec., 
+  13°  59.6'.  A  compressed  cluster  of  very  minute  stars. 
9°  from  Procyon  on  line  to  $  Gem. 

HERCULES. 

A  large  and  very  interesting  constellation,  although  not 
conspicuous  to  the  naked  eye.  Mean  R.  A.,  i6h.  50111.; 
Dec.,  +  32;  stars,  451. 

9 


130          THE    AMATEUR    TELESCOPIST  S   HANDBOOK. 

a.  (Ras  Algethi.)  R.  A.,  lyh.  gm.  385.;  Dec.,  +  14° 
30.9'.  A  splendid  double.  A  3^,  orange  ;  B  5^,  emerald 
or  bluish  green.  D.,  4.7".  Smyth  calls  this  a  lovely  ob- 
ject, one  of  the  finest  in  the  heavens. 

d.  R.  A.,  iyh.  lorn.  315.;  Dec.,  +  24°  58.3'.  A  beauti- 
ful double.  A  4,  greenish  white ;  B  8^,  grape  red.  D., 
18.1".  Due  N.  of  a  11°. 

H\  R.  A.,  i6h.  3m.  6s.;  Dec.,  +  17°  20.6'.  A  very 
pretty  double.  A  5^,  light  yellow  ;  B  7,  pale  garnet.  D., 
29.8".  Line  from  ft  Lyrae  to  ft  Here,  and  7°  on. 

p.  R.  A.,  i7h.  i9m.  535.;  Dec.,  +  37°  14.9'.  A  beauti- 
ful double.  A  4,  bluish  white  ;  B  5j,  pale  emerald.  D., 
3.89".  2°  from  n  on  line  to  Wega. 

36-37.  R.  A.,  i6h.  35m.  75.;  Dec.,  +  4°  26.1'.  A  pair 
of  blue  stars  of  mag.  6J  and  y£.  D.,  69.8".  It  is  16°  W. 
of  ft  Ophiuci,  just  S.  of  a  line  from  it  to  e  Serpentis. 

95.  R.  A.,  i7h.  56m.  505. ;  Dec.,  +  21°  35.8'.  A  lovely 
double.  A  5^,  light  apple-green  ;  B  6,  cherry  red.  D., 
6.1".  There  is  much  difference  of  opinion  as  to  the 
colors  of  these  stars ;  Macdonnell  pronounced  both 
golden-yellow.  About  I2-J0  from  a  Ophiuci  on  line 
to  ft  Lyrae. 

100.  R.  A.,  i8h.  3m.  245. ;  Dec.,  +  26°  4.8'.  A  neat 
double.  Both  mag.  7,  both  pale  white.  D.,  14.1".  i2-J° 
from  ft  Lyrae  on  line  to  a  Herculis. 

2104  2.  R.  A.,  i6h.  44m.  455.  ;  Dec.,  +  36°  6.5'.  A 
very  pretty  double.  A  6-J-,  white  ;  B  8£,  ash-colored. 
D.,  5.9".  4°  from  2,  on  line  to  ft  Draconis. 

2007  ^.  R.  A.  (1880),  i6h.  im. ;  Dec.,  +  13°  39'.  A 
very  fine  pair.  A  6J,  yellowish-white ;  B  8,  white.  D., 
32".  Line  from  ft  through  y  and  7°  on. 

2087  ^.  R.  A.  (1880),  i6h.  38m.  ;  Dec.,  +  23°  51'. 
An  exquisite  little  double.  Both  mag,  8,  both  white. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  131 

D.,  5.7".  Line  from  a  Serpentis  through  ft  Here,  and  4° 
on.  Just  S.  and  a  little  E.  of  this  is 

2  5  N.  (H.  4234.)  R.  A.,  i6h.  39m.  515.;  Dec., 
+  24°  o'.  A  small  pale-blue  planetary  nebula  which  bears 
magnifying  well.  Its  disk  is  about  8"  in  diameter,  but 
ill-defined. 

13  M.  (H.  4230-)  R.  A.,  i6h.  37m.  455.  ;  Dec.,  +  36° 
39.9'.  A  gorgeous  cluster,  one  of  the  most  magnificent 
objects  in  the  heavens.  It  blazes  toward  the  centre  and 
has  numerous  outliers.  It  was  discovered  by  Halley,  and 
is  sometimes  called  H  alley's  nebula.  It  is  faintly  visible 
to  the  naked  eye  ;  and  "  under  telescopic  aid,"  says  Olm- 
stead,  "  it  reveals  its  glories  in  a  form  truly  exciting  to  the 
beholder."  Dr.  Nichol,  more  enthusiastic,  says  :  "  Per- 
haps no  one  ever  saw  it  for  the  first  time  through  a  tele- 
scope without  uttering  a  shout  of  wonder."  It  is  almost 
on  a  line  (a  little  W.)  between  77  and  <?,  3^  from  the  for- 
mer ;  and  7°  from  a  on  line  to  £  Bootis. 

92  M.  (H.  4294.)  R.  A.,  lyh.  i3m.  465.;  Dec.,  +  43° 
15.1'.  A  globular  cluster,  very  luminous  in  centre;  a 
splendid  object.  16^°  W.  and  a  little  S.  from  ex  Lyrae 
is  a  3d  mag.,  which  is  n  Herculis.  92  M.  is  7°  from  it  on 
line  to  Polaris. 


HYDRA  (THE  WATER-SNAKE). 

A  long  winding  constellation  stretching  through  more 
than  six  hours  of  right  ascension.  Mean  R.  A.,  nh. 
26m. ;  Dec.,  —  17°  ;  stars,  370. 

a.  (Al-fard,  the  Solitary,  or  Cor  Hydras.)  R.  A.,  9  h. 
22m.  us. ;  Dec.,  —  8°  10.9'.  A  star  with  a  difficult  dis- 


132  THE    AMATEUR    TELESCOPIST  S   HANDBOOK. 

tant  companion.  A  2,  but  suspected  of  variability,  orange 
tint ;  B  10,  pale-green.  D.,  281.2". 

T\  R.  A.,  ph.  23m.  343.  ;  Dec.,  —  2°  17.2'.  A  wide 
double.  A  5^,  flushed  white  ;  B  8^,  lilac.  (Colors  ac- 
cording to  Webb,  pale-white,  dusky.)  D.,  66.2".  6°  due 
N.  of  a. 

R.  R.  A.,  i3h.  23m.  425.;  Dec.,  —  22°  42.7'.  A 
remarkable  variable.  Its  period  is  436  days,  and  appears 
to  be  diminishing.  Its  extreme  magnitudes  during  visi- 
bility are  4  and  10.  It  is  of  a  pale  orange-yellow  tint, 
and  has  a  distant  greenish  8th  mag.  companion.  D., 
138.7".  13^°  from  ft  Corvi  on  line  to  d  Scorpionis,  and 
12°  S.  and  i°  E.  of  Spica. 

10.  R.  A.,  i4h.  39m.  395.;  Dec.,  —  24°  58.4'.  A  very 
beautiful  double.  A  5-},  pale  orange  ;  B  7^,  violet  tint. 
D,,  9".  Line  ^from  6  Scorpii  (the  3d  mag.  star  2°  W. 
and  N.  of  Antares)  through  y  Scorpii  and  4^°  on. 

313  Birm.  R.  A.  (1880),  13!!.  42m.;  Dec.,  —  27°  46'. 
A  very  fine  ruby  star  ;  mag.  6^.  Line  from  d  Scorp.  to 
y  Scorp.  and  18^°  on. 

108  P.  VIII.  R.  A.,  8h.  3om.  is.;  Dec.,  +  7°  0.5'.  A 
fine  double.  A  6,  pale  yellow  ;  B  7,  rose-tint.  D.,  10.6". 
A  line  from  Procyon  to  Regulus  passes  i°  N.  of  this 
object  at  a  distance  of  13^°  from  the  former. 

27  T$  IV.  (H.  2102.)  R.  A.,  loh.  19111.  255.;  Dec., 
— 17°  35.6'.  A  fine  planetary  nebula,  bearing  magnifying 
well.  Smyth  compares  it  to  Jupiter  in  size  and  equable 
light.  Noble  suggests  that  it  resembles  a  ghost  of  Jupi- 
ter. It  is  of  a  pale  bluish  tint.  Line  from  ft  Corvi  to  e 
Corvi  and  26°  on.  2°  S.  and  a  little  W.  from  ju. 

68  M.  (H.  3128.)  R.  A.,  i2h.  33m.  345.;  Dec.,  —  26° 
7.6'.  A  pale  nebula  3'  broad  and  4'  long.  3^°  S.  and  a 
little  E.  from  ft  Corvi. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.          133 


LACERTA  (THE  LIZARD). 

A  small  constellation  formed  by  Hevelius.  Mean  R. 
A.,  22h.  ipm. ;  Dec.,  +  52°  ;  stars,  60. 

a.  R.  A.,  22h.  26m.  445.;  Dec.,  +  49°  43'.  A  star 
given  here  only  for  the  noble  field  in  which  it  is  situated. 
Line  from  y  Cassiopeae  to  ft  Cass.  and  17°  on. 

S\  R.  A.,  22h.  3om.  585.;  Dec.,  +  39°  3.9'.  A  quad- 
ruple star  which  will  be  double  only  in  a  small  telescope. 
Both  6J,  both  white.  The  other  components  are  of  mag. 
10  and  ii.  D.,  AB  22.3".  Line  from  y  Cygni  to  v  Cyg. 
and  19°  on. 

65  P.  XXII.  R.  A.,  22h.  1 4m.  6s.;  Dec.,  +  37°  13'.  A 
neat  double.  A  6J,  pale  white  ;  B  9,  livid.  D.,  15.4'. 
Line  from  ft  Lyrse  to  y  Cygni  and  24°  on.  It  closely  fol- 
lows i  Lacertae,  a  5th  mag.  star. 

75  m  VIII.  (H.  4773.)  R.  A.,  22h.  urn.  575.;  Dec., 
+  49°  19.9'.  A  fine  cluster,  quickly  followed  by  a  beau- 
tiful field.  The  cluster  is  about  16'  long.  Line  from  £ 
Cassiopeae  through  /3  Cass.  and  17°  on. 

LEO  (THE  LION). 

A  noble  constellation,  one  of  the  most  striking  in  the 
northern  hemisphere.  Mean  R.  A.,  loh.  25m.;  Dec., 
+  20°  ;  stars,  337. 

a.  (Regulus.)  R.  A.,  loh.  2m.  305.;  Dec.,  + 12°  30.3'. 
A  fine  star  with  a  distant  companion.  A  i,  flushed  white  ; 
B  8J,  pale  purple.  D.,  177".  Decidedly  difficult. 

/?.     (Denebola.)     R.   A.,   nh.  4301.  275.;  Dec.,  +  15° 


134        THE  AMATEUR  TELESCOPIST'S  HANDBOOK. 

11.2'.  A  bright  star  with  a  very  distant  companion.  A 
2^,  bluish  ;  B  8,  dull  red.  D.,  282".  Other  stars  in 
field. 

y.  (Al  Gieba.)  R.  A.,  loh.  i3m.  545.;  Dec.,  +  20° 
23.8'.  A  splendid  double  ;  according  to  Struve,  the  finest 
in  the  northern  sky.  A  2,  bright  orange  ;  B  4,  greenish 
yellow.  D.,  3.61",  and  increasing. 

6.  R.  A.,  Qh.  26m.  45.;  Dec.,  +  10°  12.1'.  A  neat 
but  difficult  double.  A  6,  pale  rose  tint  ;  B  9^,  pur- 
ple. D.,  36.8".  Carry  a  line  from  /?  ij0  S.  of  a  and  9° 
on. 

83.  R.  A.,  nh.  2im.  133.;  Dec.,  +  3°  36.7'.  A  pretty 
double.  A  8,  silvery  white  ;  B  9,  pale  rose  tint.  D., 
29.5".  It  closely  precedes  (a  little  N.)  r  Leon.,  to  find 
which  draw  a  line  from  y  Virginis  through  ft  Virg.  and 
5|°  further. 

90.  R.  A.,  nh.  28m.  595.;  Dec.,  +  17°  24.4'.  A  fine 
triple.  A  6,  silvery  white  ;  B  7  J,  purplish  ;  C  9j,  pale 
red.  D.,  AB  3.5",  AC  63.3".  AB  probably  form  a  binary 
system.  Line  from  d  Virginis  through  /?  Leon.,  and  4^° 
on. 

R.  R.  A.,  9h.  4im.  395.;  Dec.,  +  n°  56.5'.  A  superb 
vivid  red  star,  varying  in  312  days  from  mag.  5  to  10. 
Hind  says  :  "  It  is  one  of  the  most  fiery-looking  variables 
on  our  list — fiery  in  every  stage  from  maximum  to  mini- 
mum, and  is  really  a  fine  telescopic  object  in  a  dark  sky, 
about  the  time  of  greatest  brilliancy,  when  its  color  forms 
a  striking  contrast  with  the  steady  white  light  of  the  6th 
magnitude,  a  little  to  the  N."  A  line  from  a  to  Procyon 
will  pass  within  £°  S.  of  this  star,  5^°  from  a. 

1434  2.  R.  A.  (1880),  loh.  2im.;  Dec.,  -f  18°  41'. 
A  very  pretty  double.  Both  8^  (Struve),  both  orange. 
D.,  6.1".  2|°  from  y  on  line  to  d  Corvi. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  135 

95  M.  (H.  2184.)  R.  A.,  loh.  38m.  ios.;  Dec.,  +  12° 
16.3'.  A  lucid  round  white  nebula.  It  is  8|°  due  E.  of 
a.  About  J°  E.  and  somewhat  N.  of  this,  follows  another 
round  but  paler  nebula.  (96  M.,  H.  2194.) 

17  1$  I.     (H.    2203.)      R.    A.,  loh.  42m.  is.;    Dec., 
+ 13°  9.4'.     A  round  nebula  brightening  towards  the  cen- 
tre.    It  is  |°  N.  a  little  E.  from  last  object. 

18  J§L  I.     (H.    2207.)       R.  A.,  loh.  42m.  285.;    Dec., 
+ 13°  12.3'.    A  faint  round  nebula,  forming  a  pair  with  the 
last  object. 

13  13  I.  (H.  2301.)  R.  A.,  nh.  om.  ios.;  Dec., +0° 
33.5.  A  pale  white,  well-defined  elongated  nebula.  A  line 
from  y  Virginis  carried  |°  under  rj  Virg.  and  18°  on  will 
reach  this  object. 

66  M.  (H.  2377.)  R.  A.,  nh.  i4m.  225.;  Dec.,  +  13° 
34.9'.  A  large  faint  elongated  nebula.  735.  from  it 
towards  the  W.  is  another  of  similar  shape,  but  smaller. 
This  is  65  M.,  H.  2373.  They  are  less  than  i°  S.  of  a 
line  from  fi  to  a,  7^°  from  /?. 


LEO  MINOR  (THE  LESSER  LION). 

A  small  constellation  of  little  importance,  formed  by 
Hevelius.  Mean  R.  A.,  roh.  2om.;  Dec.,  +  38°  ;  stars, 
96. 

86  W  I.     (H.  2104.)     R.  A.,  loh.  2im.  6s.;  Dec.,  +29° 
4'.     An  oval  nebula  with  central  nucleus.     Line  from  a 
i  J°  W.  of  y,  and  8°  on. 

87  ip  I.     (H.  2274.)     R.  A.,  loh.  54m.  128.  ;  Dec.,  + 
29°  34'.     A  large  orbicular  nebula.     6°  from  v  Urs.  Maj. 
on  line  to  Regulus. 


136  THE   AMATEUR    TELESCOPIST'S   HANDBOOK. 


LEPUS  (THE  HARE). 

A  small  southern  constellation,  poor  to  the  eye,  but 
containing  several  very  interesting  objects.  Mean  R. 
A.,  5h.  32m. ;  Dec.,  —  20°  ;  stars,  66. 

a.  (Arneb.)  R.  A.,  5h.  27m.  525.  ;  Dec.,  —  17°  54.2'. 
A  not  easy  double.  A  3^,  pale  yellow  ;  B  9^,  gray.  D., 

35.6". 

y.  R.  A.,  5h.  4om.  ;  Dec.,  —  22°  20'.  A  beautiful 
pair,  A  4,  light  yellow,  B  6-J-,  pale  garnet.  D.,  92.9". 

R.  R.  A.,  4h.  54m.  363.  ;  Dec.,  —  14°  58.2'.  Hind's 
celebrated  "  Crimson  Star."  A  superb  object.  Says  Mr. 
Hind  :  "  It  is  of  the  most  intense  crimson,  resembling  a 
blood-drop  on  the  black  ground  of  the  sky  ;  as  regards 
depth  of  color,  no  other  star  visible  in  these  latitudes 
could  be  compared  to  it."  Line  from  6  Orionis  to  Rigel, 
and  7^°  on. 

875  2.  R.  A.,  6h.  7m.  ;  Dec.,  —  13°  7'.  A  pretty 
double.  A  8.7,  red  ;  B  9.8,  very  green.  D.,  6".  5f° 
from  ft  Can.  Maj.  on  line  to  2,  Orionis. 

79  M.  (H.  1 1 12.)  R.  A.,  5h.  19111.  535.  ;  Dec.,  —  24° 
36.9'.  A  stellar  nebula  blazing  towards  the  centre,  and 
with  a  milky  white  tinge.  A  line  from  a  to  ft  and  4°  on 
will  pass  within  less  than  i°  E.  of  this  object. 

LIBRA  (THE  BALANCE). 

A  rather  inconspicuous  zodiacal  constellation.  Mean 
R.  A.,  i5h.  8m.  ;  Dec.,  —  13°  ;  stars,  180. 

a.  (Kiffa  Australis.)  R.  A.,  ,14!!.  44m.  475;  Dec., 
—  15°  35'.  A  wide  but  fine  pair.  A  3,  pale  yellow  ;  B 
6,  light  gray.  D.,  230.8." 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  137 

ft.  (Kiffa  Borealis.)  R.  A.,  15)1.  nm.  55.  ;  Dec.,  —  8° 
58.6'.  A  very  beautiful  pale  green  star,  the  color  of 
which,  as  Webb  remarks,  is  very  unusual  among  con- 
spicuous stars.  And  he  adds  :  "  Deep  green,  like  deep 
blue,  is  unknown  to  the  naked  eye." 

i.  R.  A.,  i5h.  5m.  535. ;  Dec.,  —  19°  22.4'.  A  wide  but 
rather  difficult  pair.  A  5^,  pale  yellow  ;  B  9^,  purple. 
•D-,  57-5"'  13°  due  W.  of  ft  Scorpionis. 

62  P.  XIV.  R.  A.,  i4h.  i6m.  493.  ;  Dec.,  —  17°  15.5'. 
A  fine  double.  Both  8,  both  silvery  white.  D.,  5.4". 
Line  from  ft  Virginis  to  Spica  and  16°  on. 

1962  2.  R.  A.,  150,  32m.  435.  ;  Dec.,  —  8°  26'.  A 
striking  double.  Both  6^,  both  white,  or  yellow  accord- 
ing to  Franks.  D.,  u.8".  Line  from  0  Scorpionis  to  ft 
Scorp.  and  13°  on.  6°  from  jn  Serpentis  on  line  to  y 
Scorp. 

212  P.  XIV.  R.  A.,  i4h.  5om.  555.  ;  Dec.,  —  20° 
53.2'.  A  pretty  double.  A  6,  straw  color  ;  B  8,  orpi- 
ment  yellow.  D.,  15.1".  A  line  from  y  Scorp.  to  a  Lib. 
will  pass  within  £°  E.  of  this  star,  4^°  from  the  former. 

5  M.  (H.  4083.)  R.  A.,  i5h.  1 2m.  575.  ;  Dec.,  +  2° 
30.1'.  A  splendid  cluster  of  minute  stars,  greatly  com- 
pressed in  the  centre,  and  more  than  7'  or  8'  in  diameter. 
"  A  noble  mass,"  says  Smyth,  "  refreshing  to  the  senses 
after  searching  for  faint  objects."  8-J°  from  a  Serpentis 
on  line  to  ft  Corvi. 

LYNX. 

A  large  modern  constellation  formed  by  Hevelius.  It 
contains  little  that  is  within  the  power  of  a  small  tele- 
scope. Mean  R.  A.,  7h.  37m.  ;  Dec.,  +  50°  ;  stars,  149. 

19.  R.  A.,  7h.  i3m.  535.  ;  Dec.,  +  55°  28.6'.  A  wide 
but  pretty  triple.  A  7,  white  ;  B  and  C  both  8,  both  plum- 


138          THE    AMATEUR    TELE$COPIST*S    HANDBOOK. 

colored.     D.,  AB    14.3",  AC    215.2".     27°  from    Polaris 
on  line  to  Pollux. 

40.  R.  A.,  ph.  1301.  515.  ;  Dec.,  +  34°  49.5'.     A  fine 
deep   orange-red   star   of   mag.   4.     This   is    sometimes 
known   as  a.     Line   from  2,  Urs.   Maj.  to  y  Urs.  Maj. 
and  33°  on. 

41.  R.  A.,  ph.  2im.  275.  ;  Dec.,  +  46°  5.3'.     A  wide 
double.     A  6£,  B  8J,  both  bluish.     D.,  81.6".    6£°  from  A 
Urs.  Maj.  on  line  to  H  Urs.  Maj. 

LYRA  (THE  LYRE). 

A  small  but  splendid  constellation,  perhaps  the  finest, 
in  proportion  to  its  size,  of  them  all.  Mean  R.  A.,  i8h. 
3om.;  Dec.,  +  36°;  stars,  166. 

a.  (Wega,  Vega  or  Lyra.)  R.  A.,  i8h.  3301.  138.  ; 
Dec.,  +  38°  40.9".  A  grand  pale-sapphire  star  of  the 
first  magnitude,  one  of  the  most  splendid  in  the  heavens. 
It  has  a  minute  blue  companion  of  mag.  n,  distant  48.1", 
but  although  it  has  been  seen  by  some  observers  with 
less  than  2  inches,  I  doubt  if  the  average  eye  can  see 
it  with  anything  under  3^  inches. 

/?.  (Sheliak.)  R.  A.,  i8h.  46m.  is.  ;  Dec.,  +  33°  14.1'. 
A  variable  star  ranging  from  mag.  3^  to  4^  in  i2d.  2ih. 
53m.  It  has  4  companions  of  which  our  observer  may 
see  3.  B  8,  pale  gray  ;  D  8J,  faint  yellow  ;  E  9,  lilac  ; 
D.,  AB  45.6",  AD  66.5"  AE  85.6".  A  is  called  white  by 
Smyth,  yellow  by  Webb. 

6.  R.  A.,  i8h.  49m.  525.  ;  Dec.,  +  36°  50.3'.  A  star 
in  a  splendid  low-power  field,  with  a  distant  companion 
known  as  (T.  A  4,  orange  ;  B  5,  white. 

£.     R.  A.,  i8h.  40111.  415. ;  Dec.,  +  39°  33.2'.      A  won- 


THE   AMATEUR   TELESCOPlST's   HANDBOOK.  139 

derful  multiple  system.  Under  the  slightest  optical  aid 
— an  opera-glass  is  quite  sufficient — this  star  is  seen  dou- 
ble ;  and  with  a  high  power  each  of  the  components  is 
seen  to  be  double.  Between  them  are  3  minute  stars, 
only  one  of  which,  of  mag.  9^,  will  be  seen  with  a  small 
telescope.  Each  of  the  minute  pairs  is  a  binary  ;  the  com- 
ponents of  f1  having  a  period  of  about  2,000  years,  those 
of  s*  a  period  of  about  1,000  years,  and  possibly  both 
pairs  revolve  around  their  common  centre  of  gravity  in 
something  less  than  1,000,000  years.  D.,  e1  f2,  207"; 
components  of  t1,  3.16";  of  £2,  2.58".  Magnitudes,  f1  5, 
£*  6J.  Less  than  2°  E,  and  somewhat  N.  of  a. 

<?.  R.  A.,  i8h.  4om.  595.;  Dec.,  +  37°  29.4'.  A  fine 
double.  A  5,  topaz  ;  B  5^,  greenish.  2°  from  ct,  forming 
with  it  and  £  a  nearly  equilateral  triangle.  D.,  44.1". 

rj.  R.  A.,  i9h.  lorn,  is.;  Dec.,  +38°  57.5'  A  neat 
double.  A  5,  sky-blue  ;  B  9,  violet  tint.  A  is  yellow,  ac- 
cording to  Knott.  D.,  28.5".  ii°  of  a  line  from  a  to  y 
Cygni,  and  6°  from  the  former. 

2372  2.  R.  A.,  i8h.  38m.  us.  Dec.,  +34°  38.2'. 
A  double  star.  A  7,  white  ;  B  9,  clear  blue.  D.,  24.9". 
3°  from  a  on  line  to  8,  Aquilae. 

56  B.  R.  A.,  i8h.  39m.  415.;  Dec.,  +  44°  49.4'.  A 
double  star.  A  7,  yellow  ;  B  9,  bluish  white.  D.,  26.3". 
6°  from  e  on  line  to  Polaris. 

91  B.  R.  A.,  i8h.  5om.  515.;  Dec.,  +  33°  49.7'.  A 
beautiful  double  (really  triple).  A  6,  yellow  ;  B  7,  blue. 
D.,  45.3".  Knott  calls  this  "a  charming  miniature  of  ft 
Cygni  ;  the  colors  very  fine."  Less  than  i°  from  /3  on 
line  to  6,  the  star  just  S.  of  77. 

2470  2.  R.  A.,  i9h.  4m.  445.  ;  Dec.,  -f  34°  35.5'.  A 
pretty  double.  A  7,  B  9,  both  white.  D.,  13.3".  2^° 
from  y  on  line  to  6. 


140          THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

57  M.  (H.  4447.)  R.  A.,  i8h.  4901.  285.  ;  Dec.,  + 
32°  53-6'.  A  wonderful  annular  nebula  ;  the  only  one  of 
the  few  in  the  heavens  that  is  within  the  reach  of  a  small 
telescope.  It  is  a  somewhat  elliptical  ring  of  light,  about 
80"  in  diameter.  According  to  Sir  W.  Herschel,  it  is  dis- 
tant from  us  950  times  as  far  as  Sirius  !  It  was  consid- 
ered that  Secchi  had  resolved  this  nebula  into  stars,  but 
Muggins  finds  only  a  gaseous  spectrum.  About  J  the 
distance  between  /3  and  y. 

56  M.  (H.  4485.)  R.  A.,  i9h.  i2m.  i6s.;  Dec.,  + 
29°  59.3'.  A  globular  cluster  of  very  minute  stars,  nebu- 
lous in  a  small  telescope.  It  is  in  a  splendid  field.  5^° 
from  ft  on  line  to  /3  Cygni. 


MONOCEROS  (THE  UNICORN). 

A  large  modern  constellation  devised  by  Bartschius, 
Kepler's  son-in-law.  Mean  R.  A.,  7h.  28m. ;  Dec.,  — 10°  ; 
stars,  220. 

5.  R.  A.,  6h.  9m.  305. ;  Dec.,  6°  14.4'.  A  fine  orange 
star  of  mag.  4^.  7^°  from  H  Orionis  on  line  to  Procyon. 

8.  R.  A.,  6h.  1 7m.  565.  ;  Dec.,  +  4°  38.8'.  A  fine 
double  in  a  glorious  low-power  field.  A  4^,  golden  yel- 
low ;  B  7,  lilac.  D.,  13.9".  Line  from  Aldebaran 
through  A,  Orionis  (the  north  star  of  the  3  in  the  head), 
and  13°  on.  Nearly  8°  from  a  Orionis. 

10.  R.  A.,  6h.  22m.  315.  ;  Dec.,  —  4°  41.9'.     A  wide 
double  in   an  elegant   group.      A  6,  pale  yellow  ;  B  9, 
orange.     D.,  76.9".     It  is  nearly   (a  trifle  S.)  on  a  line 
from  H  Orionis  to  Procyon,  nj°  from  the  former. 

11.  R.  A.,  6h.  23m.  295.;  Dec.,  —  6°  57.7'.     An  ele- 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK.  141 

gant  triple,  requiring  high  powers.  Sir  W.  Herschel 
called  it  one  of  the  most  beautiful  sights  in  the  heavens. 
A  6J,  B  7,  C  8,  all  white.  D.,  AB  7.2",  AC  9.6",  BC  2.7". 
Line  from  Aldebaran  to  Bellatrix  and  2oJ°  on. 

104  P.  VI.  R.  A.,  6h.  22m.  45.  ;  Dec.,  +  o°  31'.  A 
wide  double.  A  7^-,  topaz  yellow  ;  B  8-J,  plum  tinge.  D., 
66.1".  B  is  itself  double  in  powerful  telescopes.  "A 
low-power  field  includes  77,  a  fine  6th  mag.  yellow  star, 
with  this  pair  np  and  another  s p  ;  a  noble  spectacle." 
(Webb.)  20°  from  Procyon  on  line  to  /3  Eridani. 

116  P.  VII.  R.  A.,  7h.  22m.  428.;  Dec.,  —  11°  20'. 
A  double  star  ;  in  reality  a  delicate  quintuple.  A  7, 
yellow  ;  B  9,  violet.  D.,  23.4".  Line  from  A  Eridani 
(the  4th  mag.  star  to  the  right  of  Rigel)  to  H  Orionis, 
and  24^°  on. 

2  ]£  VII.  (H  "1424.)     R.  A.,  6h.  2501.  45.  ;  Dec.,  +  5° 
1.3'.     A  beautiful,  brilliant  cluster  of  stars  from  mag.  7  to 
14,  the  latter  running  in  rays.     Line  from  ft  Eridani, 
midway  between  lowest  and  middle  stars  of  Orion's  belt, 
and  i4j°  on. 

3  1$  VIII.     (H.  1429.)     R.   A.,  6h.  28m.  465. ;  Dec., 
+  8°  26.5.'     A  large  and  rich  cluster,  but  little  condensed. 
Line  from  Bellatrix  to  Betelgeuse  and  10°  on. 

27  #  V.  (H.  1440.)  R.  A.,  6h.  34m.  555. ;  Dec.,  +  9° 
59.8'.  A  magnificent  stellar  field,  containing  15,  a  green- 
ish 6th  mag.  star.  Line  from  y  Orionis  through  a  Or. 
and  nf°  on  ;  the  object  will  be  found  i°  due  N.  of  the 
point  so  reached. 

27  13  VI.  (H.  1465.)  R.  A.,  6h.  46m.  75.  ;  Dec., 
o°  35.3'.  A  bright  cluster,  divided  into  3  rich  groups 
resembling  3  arms  of  a  cross.  Line  from  Aldebaran 
through  Betelgeuse  and  15!°  on. 

50  M,     (H.  1483.)     R.  A.,  6h.  57m.  415.     Dec.,  —  8° 


142  THE    AMATEUR    TELESCOPIST  S   HANDBOOK. 

10.7'.  A  superb  cluster,  irregularly  round  and  very  rich. 
A  line  from  Sirius  to  Procyon  will  pass  i°  S.  E.  of  this 
cluster,  9-J°  from  Sirius. 

34  ]p  VIII.  (H.  1506.)  R.  A.,  yh.  gm.  205.  ;  Dec., 
—  10°  5.7'.  A  rich  field,  containing  an  oval  mass  of  stars 
and  a  fine  double  star.  (1052  ^.)  Mags.  8  and  8-J-,  both 
white.  Line  from  a  Leporis  to  6  Can.  Maj.  and  5^°  on. 

22  3£  VI.  (H.  1637.)  R.  A.,  8h.  8m.  8s.  ;  Dec.,  - 
5°  28'.  A  rich  splashy  cluster  containing  a  splendid 
group.  Its  alignment  is  very  difficult,  but  it  may  be 
picked  up  thus :  Carry  a  line  from  ft  Can.  Min.  to 
Procyon  and  i  ij°  on  ;  from  the  point  thus  reached,  line 
due  S.  2|°. 

OPHIUCUS  (THE  SERPENT-BEARER). 

A  large  and,  to  the  naked  eye,  rather  dull  constellation. 
Mean  R.  A.,  i6h.  50111.  ;  Dec.,  —  3°  ;  stars,  289. 

36.  R.  A.,  i7h.  8m.  345.  ;  Dec.,  —  26°  25.3'.  A  fine 
double.  A  4j,  ruddy  ;  B  6J,  pale  yellow.  D.,  5".  nj° 
from  Antares  on  line  to  ff  Sagit. 

39.  R.  A.,  i7h.  nm.  1 8s.  ;  Dec.,  —  24°  9.9'.  A  very 
beautiful  double.  A  5^,  pale  orange ;  B  7^,  blue.  D., 
10.7".  17°  from  A  Sagit.  on  line  to  d  Scorp. 

53.  R.  A.,  i7h.  2901.  235.  ;  Dec.,  +  9°  39.8'.  A  wide 
double.  A  6,  B  8,  both  bluish.  D.,  41.2".  3°  due  S. 
of  a. 

6 1.  R.  A.,  i7h.  39m.  35.  ;  Dec.,  +  2°  37.6'.  A  pretty 
double.  A  6|,  B  7,  both  white.  D.,  20.2."  i°  W.  of  y, 
and  2°  S.  of  /?. 

67.  R.  A.,  i7h.  55m.  8s.  ;  Dec.,  -f  2°  56.2'.  A  wide 
double.  A  4,  straw-color ;  B  8,  purple.  D.,  54.7".  A 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  143 

little  W.  and  S.  of  this  is  a  fine  orange  star  which  is  422 
Birm.  Line  from  61  through  y  and  3°  on. 

124  B.  R.  A.,  i;h.  im.  los.  ;  Dec.,  —  i°  30.2'.  A 
double  star.  A  7,  B  9,  both  white.  D.,  20.3".  16°  from 
a  on  line  to  a  Scorp. 

12  M.  (H.  4238.)  R.  A.,  i6h.  4im.  315.  ;  Dec.,  —  i° 
45.9'.  A  fine  rich  globular  cluster,  condensed  towards 
centre.  Nebulous  in  small  telescope.  9°  from  2,  on  line 
to  H. 

10  M.  (H.  4256.)  R.  A.,  i6h.  5im.  225.  ;  Dec.,  —  3° 
56.8'.  A  rich  globular  cluster,  blazing  towards  centre. 
About  8'  in  diameter.  It  is  more  easily  resolved  than  12 
M.  Of  a  lucid  white  tint.  Line  from  a  Scorp.  to  8,  Oph. 
and  9°  on. 

19  M.  (H.  4264.)  R.  A.,  i6h.  55m.  485. ;  Dec.,  —  26° 
6.9'.  A  fine  globular  cluster,  nebulous  in  small  telescope, 
of  a  creamy  white  tint.  8°  from  Antares  on  line  to  a 
Sagit. 

9  M.  (H.  4287.)  R.  A.,  i7h.  i2m.  375.  ;  Dec.,  -  18° 
24.2'.  A  globular  cluster  of  excessively  minute  stars, 
brightening  towards  centre.  Nebulous  in  small  telescope. 
14^°  from  Antares  on  line  to  6  Aquilse. 

14  M.  (H.  43I5-)  R-  A->  !7h.  3im-  5°s-  ;  Dec.,  —  3° 
11.2'.  A  nebulous-looking  cluster,  rather  faint  in  small 
telescope,  but  very  interesting.  8°  from  ft  on  line  to  9. 

23  M.  (H.  4346.)  R.  A.,  i7h.  5om.  285. ;  Dec.,  —  18° 
58.9'.  An  "  elegant  sprinkling  "  of  telescopic  stars  ;  a 
grand  low-power  field.  Line  from  a  Sagit.  to  ju  Sagit. 
and  4^°  on. 

IT  JJ[  VI.  (H.  4268.)  R.  A.,  i6h.  57m.  445.  ;  Dec., 
—  24°  36.3'.  A  globular  cluster  of  small  stars,  con- 
densed towards  centre.  8°  from  Antares  on  line  to  ff 
Sagit. 


144        THE  AMATEUR  TELESCOPIST'S  HANDBOOK. 


ORION. 

The  most  gloriously  beautiful  of  all  the  constellations  ; 
splendid  alike  to  the  eye  and  to  the  telescope.  Mean  R. 
A.,  5h.  26m.  ;  Dec.,  o°  ;  stars,  304. 

a.  (Betelgeuse.)  R.  A.,  5h.  39111.  145.  ;  Dec.,  +  7° 
23'.  A  brilliant  star  which  is  probably  variable  to  a 
slight  degree,  but  never  falls  below  the  ist  magnitude. 
Its  color  is  extremely  striking.  "  A  most  beautiful  and 
brilliant  gem  !  singularly  beautiful  in  color,  a  rich  topaz  ; 
in  hue  and  brilliancy  different  from  any  other  star  I 
have  seen. "  (Lassell.)  "  Look  at  a  and  fi  alternately  ; 
even  a  small  telescope  will  show  the  beauty  of  the  con- 
trast." (Webb.) 

/?.  (Rigel.)  R.  A.,  5h.  pm.  155. ;  Dec.,  —  8°  19.9'. 
A  splendid  star  with  a  small  blue  companion  of  mag.  9. 
D.,  9.5".  Rigel  itself  has  a  blue  tint  which  Knott  pro- 
nounces one  of  the  finest  shades  among  the  stars.  The 
comes  is  a  celebrated  test-object  ;  some  abnormally  keen- 
eyed  observers,  like  Dawes  and  Burnham,  have  seen  it 
with  less  than  2  inches,  but  2-J  inches,  in  most  favorable 
weather,  is  the  very  lowest  aperture,  I  think,  that  may 
ever  be  expected  to  show  this  little  star  to  the  average 
eye. 

d.  R.  A.,   5h.  26m.   235.;    Dec.,  —  o°  22.9'.      A  very 
beautiful  double,  though  wide.    A  2,  brilliant  white  ;  B  7, 
violet.     D.,  52.8". 

e.  R.  A.,  5h.  3om.  385. ;  Dec.,  —  i°  16.4'.     A  star  with 
a  difficult  distant  companion.     A  2^,  bright  white  ;  B  10, 
pale  blue.     D.,  179.9". 

2.  R.  A.,  5h.  35m.  128.;  Dec.,  —  2°  0.2'.  A  fine  but 
difficult  triple.  A  3,  topaz  yellow,  and  very  bright  for  its 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  145 

magnitude;  B  6J,  light  purple;  C  10,  gray.  D.,  AB  2.61", 
AC  57.1".  B  is  the  star  to  which  Struve  applied  what 
Chambers  calls  his  "  terrible  adjective,"  olivaceasubrubi- 
cunda. 

\.  R.  A.,  5h.  29111.  55.;  Dec.,  +  9°  51.5'.  An  elegant 
double.  A  4,  pale  white  ;  B  6,  violet  (yellow  and  blue, 
Dembowski}.  D.,  4.3".  This  is  the  northernmost  of  the 
3  little  stars  in  the  head. 

p.  R.  A.,  5h.  ym.  325.;  Dec.,  +  2°  43.7'.  A  beautiful 
double.  A  5,  orange  ;  B  9,  smalt  blue  ;  colors  very  de- 
cided. D.,  7.1."  This  is  5|°  N.  W.  of  #,  and  the  stars  of 
the  belt  point  almost  upon  it — a  little  above. 

ff.  R.  A.,  5h.  33m.  35.;  Dec.,  —  2°  38'.  An  extraor- 
dinary multiple  system  ;  a  double-quadruple  star  with  2 
stars  between  the  systems.  A  small  telescope  will  show 
it  as  a  triple.  A  4,  bright  white  ;  B  8,  bluish  ;  C  7,  grape 
red.  D.,  AB  12.7",  AC  41. 6".  Less  than  i°  S.W.  of  <?. 

23.  R.  A.,  5h.  17111.  35.;  Dec.,  +  3°  26.3'.  A  neat 
double.  A  5,  white  ;  B  7,  pale  gray.  D.,  31.1".  3°  from 
y  on  line  to  ft. 

31.  R.  A.,  5h.  23m.  595.;  Dec.,  —  i°  10.8'.  A  lovely 
golden  star  of  mag.  5^.  It  has  a  very  difficult  blue 
comes  of  mag.  n.  D.,  12.7".  i^°  from  d  on  line  to  ft. 

96  Birm.  R.  A.,  4h.  59m.  435.;  Dec.,  +  i°  1.6'.  A 
splendid  fiery  red  star,  mag.  7.  Line  from  Sirius  through 
rj  and  6°  on. 

589  2.  R.  A.  (1880),  4h.  38m.  ;  Dec.,  +  5°  5'.  A 
beautiful  double,  possibly  binary.  Both  8,  both  yellowish 
white.  D.,  4.5".  Line  from  /3  to  ft  Erid.  and  12°  on. 

278  P.  IV.  R.  A.,  4h.  56m.  i8s.;  Dec.,  +  i°  26.8'.  A 
neat  double.  A  8J,  silvery  white  ;  B  9,  pale  blue.  D., 
13.8".  Line  from  /3  Can.  Maj.  to  u  Or.  and  16°  on. 
About  i°  W.  and  somewhat  N.  of  96  Birm. 

10 


146  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

42  M.  (H.  1179.)  R.  A.  (of  6),  5h.  29111.  525.;  Dec., 
—  5°  27.7.  The  Great  Nebula  in  Orion.  An  overwhelm- 
ing object :  a  vast  tract  of  nebulous  light,  faintly  visible 
to  the  naked  eye,  and  growing  in  awful  impressiveness 
with  every  increase  of  optical  aid.  In  the  angle  of  the 
strange  gap  in  the  nebula  which  is  sometimes  called  the 
Fish's  Mouth,  lies  0,  a  multiple  star,  usually  called  the 
Trapezium,  from  the  figure  formed  by  its  principal  stars. 
It  is  readily  seen  with  powers  of  from  50  upwards.  The 
components  of  the  Trapezium  are  of  mags.  6,  7,  7^,  and  8 
In  addition  to  these,  0  contains  two  most  minute  stars  of 
mag.  10 J  and  12,  which  cannot  be  seen  except  with 
higher  powers  and  larger  apertures  than  the  amateur  can 
generally  command.  There  are  even  other  stars  in  or 
near  the  Trapezium,  but  they  seem  not  to  belong  to  the 
system. 

78  M.  (H.  1267.)  R.  A.,  5h.  4im.  6s.  ;  Dec.  +0°  2.1'. 
Two  stars  in  a  "  wispy  "  nebula.  Mags.  8J  and  9.  The 
object  resembles  a  binuclear  nebula.  Faint,  but  most 
interesting.  7^°  from  a  on  line  to  ft  Leporis. 


PEGASUS. 

An  extensive  constellation,  the  interest  of  which,  how- 
ever, can  hardly  be  considered  proportional  to  its  size. 
Mean  R.  A.,  2zh.  50111.  ;  Dec.,  +  20°  ;  stars,  393. 

f.  (Enif.)  R.  A.,  2ih.  38m.  475. ;  Dec.,  +  9°  22.2'.  A 
star  with  a  distant  companion.  A  2  J,  yellow  ;  B  9,  violet. 
D.,  140.2". 

i.  R.  A.,  2ih.  1 7m.  os.  ;  Dec.,  +  19°  20'.  A  pretty 
but  not  easy  double.  A  4,  pale  orange  ;  B  9,  purplish. 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK.  147 

D.,  37.1".  Line  from  Altair  to  ft  Delphini  (the  brightest 
in  that  asterism),  and  12^°  on. 

3.  R.  A.,  2ih.  32111.  145.  ;  Dec.,  +  6°  7.5'.  A  neat 
double.  A  6,  white  ;  B  8,  pale  blue.  D.,  39.3".  A  pretty 
little  double  in  field,  8"  apart.  Line  from  e  Peg.  to  J3 
Aquarii ;  at  a  point  3^°  from  e,  draw  a  line  about  J°  W., 
and  it  will  reach  this  star. 

33.  R.  A.,  22h.  i8m.  2is.  ;  Dec.,  +  20°  17.5'.  A  dou- 
ble star.  A  6£,  yellowish  ;  B  8,  pale  gray.  D.,  63.3". 
Line  from  fi  Capric.  to  e  and  14^°  on. 

2848  2.  R.  A.,  2ih.  52m.  305.;  Dec.,  +  5°  25'.  A 
pretty  double.  A  8,  white  ;  B  _8|-,  yellowish  or  red.  D., 
10.6".  5^°  from  s  on  line  to  y  Aquar. 

306  P.  XXII.  R.  A.,  23h.  2m.  125.  ;  Dec.,  +  32° 
13.8'.  A  fine  double.  A  7,  bright  white  ;  B  8^,  sapphire 
blue.  D.,  8.6".  14°  from  a  Androm.  on  line  to  2,  Cyg. 

216  P.  XXIII.  R.  A.,  23!!.  47m.  215.  ;  Dec.,  +  11° 
18.8'.  A  neat  double.  Both  8J,  both  silvery  white.  D., 
18.7".  5J°  exactly  S.  W.  of  y. 

15  M.  (H.  4670.)  R.  A.,  2ih.  24m.  345.  ;  Dec.,  + 
11°  40.3'.  A  splendid  globular  cluster,  nebulous  in  small 
telescope,  but  resolvable  with  a  comparatively  moderate 
aperture.  There  are  some  stars  in  the  field,  but  Smyth 
remarks  that  the  globular  mass  strikes  the  senses  as 
being  almost  infinitely  beyond  these  apparent  comites. 
Line  from  6  to  f,  and  4^°  on. 


PERSEUS. 

A  brilliant  and  beautiful  constellation,  situated  in  a 
very  fine  portion  of  the  Milky  Way.  Mean  R.  A.,  3!!. 
1 6m. ;  Dec., +  50°  ;  stars,  196. 


148  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

P.  (Algol,  the  Demon.)  R.  A.,  3h.  im.  25.;  Dec.,  + 
40°  31.9'.  A  wonderful  variable,  the  most  conspicuous 
of  all  the  regularly  variable  stars.  Its  period  is  2d. 
2oh.  49m.,  and  its  range  from  mag.  2  to  4.  Its  time  of 
decrease  and  increase  together  occupy  about  7  hours, 
and  it  remains  at  minimum  but  18  minutes.  Line  from 
fi  Aurigae  through  Capella  and  24°  on  ;  or  it  may  be 
recognized  as  the  first  conspicuous  star  9^°  S.  a  little  W. 
from  a. 

rj.  R.  A.,  2h.  42m.  405.  ;  Dec.,  4-  55°  26.3'.  A  beauti- 
ful double.  A  5,  orange  ;  B  8J,  smalt  blue  ;  colors  clearly 
contrasted.  D.,  28.4".  Line  from  a  to  y  and  3°  on. 

58.  R.  A.,  4h.  29m.  25. ;  Dec.,  +  41°  2.3'.  A  neat 
triple.  A  5^,  orange  tint ;  B  71,  greenish  ;  C  9,  lilac. 
D.,  BC  1 1.8".  8J°  from  Capella  on  line  to  £. 

220  P.  II.  R.  A.,  2h.  53m.  25.  ;  Dec.,  +  51°  54.9'. 
A  neat  double.  A  6,  silvery  white  ;  B  8,  sapphire  blue. 
D.,  1 2.1".  About  2°  S.  a  little  W.  from  y. 

104  B.  R.  A.,  2h.  54m.  445.  ;  Dec., +31°  58.6'.  A 
pretty  double.  A  7,  yellow ;  B  8J,  blue.  D.,  8.8".  23° 
from  fi  Androm.  on  line  to  Aldebaran. 

76  M.  (H.  385.)  R.  A.,  ih.  35m.  25.  ;  Dec.,  +  51°  1.8'. 
An  oval,  pearly  white  nebula,  binuclear,  and  pronounced 
by  Webb  a  curious  miniature  of  the  Dumb-bell  nebula. 
It  is  close  to  and  N.  of  <p,  the  4th  mag.  star  9°  from  y 
Androm.  on  line  to  y  Cassiop. 

33  ]£  VI.  (H.  512.)  R.  A.,  2h.  nm.  205.;  Dec.,  + 
56°  38.5'.  A  gorgeous  cluster,  followed  closely  by  34  IJt 
VI.  (H.  521),  another  equally  splendid  mass,  the  two 
groups  forming  what  is  usually  called  the  cluster  in  the 
sword-handle  of  Perseus.  One  of  the  central  stars  in  the 
second  group  is  of  a  fine  ruby  color.  The  two  clusters 
are  in  the  same  field  with  a  low  power,  and  form  one  of 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  149 

the  most  magnificent  telescopic  objects  in  the  heavens. 
Just  S.  of  a  line  from  6  Cassiop.  to  y  Pers.,  and  midway 
between  them. 

34  M.  (H.  584.)  R.  A.,  2h.  34m.  575,;  Dec.,  +  42° 
15.7'.  A  beautiful  scattered  cluster.  "A  very  grand  low- 
power  field,  one  of  the  finest  objects  of  its  class."  (Webb.) 
Just  N.  of  a  line  from  y  Androm.  to  e  Pers.,  and  7j°  from 
the  former. 

25  J$  VI.  (H.  658.)  R.  A.,  3h.  7m.  265.;  Dec.,  4- 
46°  49.4'.  A  beautiful  compressed  cluster,  called  by 
Smyth  "an  elegant  sprinkle."  "A  low  power  shows  a 
very  faint  large  cloud  of  minute  stars  beautifully  bordered 
by  a  foreshortened  pentagon  of  larger  ones."  (Webb.) 
Midway  between  a  and  K  the  4th  mag.  star  S.  and  W. 
of  a. 

88  ]$  VIII.  (H.  717.)  R.  A.,  3h.  24m.  365.;  Dec.,  +• 
36°  56.7'.  A  large  cluster  of  minute  stars  ;  about  60  in 
the  group.  6°  from  Algol  on  line  to  Aldebaran. 

61  ]£  VII.  (H.  820.)  R.  A.,  4h.  6m.  525.  ;  Dec.,  +  50° 
57.5'.  A  rich  cluster,  the  larger  stars  arranged  in  curves. 
11°  from  y  on  line  to  Capella. 


PISCES  (THE  FISHES). 

A  large  but  particularly  dull-looking  constellation. 
Mean  R.  A.,  oh.  25m.;  Dec.,  +  20°;  stars,  257. 

a.  R.  A.,  ih.  56m.  2 is.;  Dec.,  +  2°  14'.  A  close 
double.  A  5,  B  6.  The  most  extraordinary  differences 
of  opinion  exist  as  to  the  colors  of  the  components. 
Smyth  calls  them  pale  green  and  blue  ;  Dawes,  both 
white,  etc.  D.,  3.08"  and  decreasing. 


150          THE    AMATEUR    TELESCOPIST's    HANDBOOK. 

3.  R.  A.,  ih.  ym.  595.;  Dec.,  +  6°  43.7'.  A  fine 
double.  A  6,  silver  white  ;  B  8,  pale  gray.  D.,  24.7". 
Line  from  rj  Erid.  through  Mira  and  19°  on. 

ip1.  R.  A.,  oh.  59m.  475.;  Dec.,  +  20°  53'.  A  fine 
double.  Both  5^,  both  silvery  white.  D.,  29.8".  Line 
from  S  Cassiop.  to  /?  Androm.  and  14°  on. 

35.  R.  A.,  oh.  9m.  i8s.  ;  Dec.,  +  8°  12.6'.  A  fine 
double.  A  6,  pale  white;  B  8,  violet  tint.  D.,  n.6". 
Line  from  a  Androm.  to  y  Pegasi  and  5 j°  on. 

38.  R.  A.,  oh.  nm.  445.;  Dec.,  +  8°  15.8'.  An  elegant 
double.  A  ;J,  light  yellow  ;  B  8,  flushed  white.  D.,  4.5". 
"  Those  sage  astrologers  who  dubbed  Pisces  a  most  ma- 
lignant sign,  ought  to  have  contemplated  this  beautiful 
object ;  had  this  been  done,  every  notion  of  stellar  un- 
propitiousness  and  malevolence  must  have  vanished." 
(Smyth.)  f°  nearly  due  E.  of  last  object. 

51.  R.  A.,  oh.  26m.  435.;  Dec.,  +  6°  20'.  A  fine  but 
difficult  double.  A  6|,  pearl  white  ;  B  9,  lilac  tint.  D., 
28.4".  9^°  from  y  Peg.  on  line  to  ?/  Ceti. 

55.  R.  A.,  oh.  34m.  8s.  ;  Dec.,  +  20°  50.7'.  A  very 
beautiful  double.  A  6,  orange  ;  B  9,  deep  blue,  but 
rather  faint.  A  fine  specimen  of  opposed  colors.  D., 
6.34."  Line  from  a  Cassiop.  to  d  Androm.  and  9°  on. 

65.  R.  A.,  oh.  43m.  583.  ;  Dec.,  +  27°  6.7'.  A  fine, 
close  double.  A  6,  B  7,  both  pale  yellow.  D.,  4.3". 
Some  observers  call  both  mag.  6.  About  8J°  from  a 
Androm.  on  line  to  fi  Arietis. 

77.  R.  A.,  ih.  om.  8s.  ;  Dec.,  +  4°  19.3'.  A  fine 
double.  A  7^,  pale  white  ;  B  8,  pale  lilac.  D.,  33.3". 
Line  from  3,  Androm.  to  8  Pise,  and  3°  on. 

100.  R.  A.,  ih.  29m.  is.  ;  Dec.,  +  11°  59.8'.  A  pretty 
double.  A  7,  white  ;  B  8,  pale  gray.  D.,  16.4".  Line 
from  Mira  through  a  and  12°  on. 


THE    AMATEUR    TELESCOPIST's   HANDBOOK.  151 

251  P.  O.  R.  A.,  oh.  53m.  455.  ;  Dec.,  —  o°  11.4'. 
A  neat  double.  A  8,  pale  orange  ;  B  9,  clear  blue.  D., 
20".  ioj°  from  0'  Ceti  on  line  to  y  Pegasi. 

PlSCIS   AUSTRALIS    (THE    SOUTHERN    FlSH). 

A  small  constellation,  important  only  for  its  beautiful 
lucida.  Mean  R.  A.,  22h.  15111.  ;  Dec.,  —  29°  ;  stars,  77. 

a.  (Fomalhaut.)  R.  A.,  22h.  5im.  345.  ;  Dec.,  —  30° 
12.3'.  A  fine  reddish  star  with  a  very  distant  dusky  blue 
companion  of  mag.  9^.  Difference  of  R.  A.,  4.83. 

SAGITTA  (THE  ARROW). 

A  diminutive  constellation  in  the  Milky  Way.  Mean 
R.  A.,  i9h.  33m.  ;  Dec.,  +  18°  30'  ;  stars,  34. 

£.  R.  A.,  19!!.  32m.  i8s.  ;  Dec.,  +  16°  12.9'.  A  star 
with  distant  companion.  A  6,  pale  white  ;  B  8,  light 
blue.  D.,  92.2".  6^°  from  y  Aquilse  on  line  to  Wega. 

d.  R.  A.,  2oh.  5m.  55.  ;  Dec.,  +  20°  35.2'.  A  triple. 
A  7,  pale  topaz  ;  B  9,  gray  ;  C  8,  pearly  yellow.  B  is 
very  difficult.  D.,  AB  11.5",  AC  76.4".  Line  from  ft 
Ceph.  to  y  Cyg.  and  19°  on. 

X.  R.  A.,  i9h.  55m.  55.  ;  Dec.,  +  17°  13'.  A  6th  mag. 
orange  star,  the  lucida  of  a  beautiful  group  containing  a 
smaller  very  red  star,  and  a  pretty  little  loth  mag.  pair. 
7j°  from  y  Aquilse  on  line  to  £  Cyg.' 

SAGITTARIUS  (THE  ARCHER). 

A  large  and  important  zodiacal  constellation.  Mean 
R.  A.,  i9h.  1501.  ;  Dec.,  -  44°  ;  stars,  339. 


152  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

/*'.  R.  A.,  i8h.  7m.  los.  ;  Dec.,  —  21°  5.2'.  A  triple 
star.  A  3-J,  pale  yellow  ;  B  9^,  blue  ;  C  10,  reddish.  D., 
AB  48.3",  AC  50.1".  It  is  the  4th  mag.  star  6°  N.W. 
of  A. 

294  P.  XVII.  R.  A.,  iyh.  52111.  os.  ;  Dec.,  —  30°  14.9'. 
A  fine  double.  A  6,  B  71,  both  strong  yellow.  D.,  5.6". 
i|°  due  W.  of  y. 

8028  Lacaille.  R.  A.,  19!!.  5m.  325.  ;  Dec.,  —  34° 
0.5'.  A  pretty  double.  Both  mag.  7.  D.,  15".  A  line 
from  0  to  £,  carried  4°  on,  reaches  a  point  i£°  due  W.  of 
this  star. 

5112  h*.  R.  A.,  i9h.  i7m.  45.;  Dec.,  — 18°  12'.  A 
striking  triple  (really  quintuple).  All  3  of  mag.  8.  D., 
AB  23.5",  AC  20."  E.  of,  and  very  close  to,  p  and  p2,  the 
close  naked-eye  pair  4^°  N.  E.  from  ?r. 

505.  Birm.  R.  A.,  19!!.  28m.  os.;  Dec.,  — 16°  36.8'.  A 
fine  ruby  star  of  mag.  6^.  A  line  from  d  to  TT,  and  7^°  on, 
reaches  a  point  less  than  i°  due  S.  of  this  star. 

3702  a.  h.  (H.  4324.)  R.  A.,  i7h.  38m.  295.;  Dec.,— 
33°  3^.5'.  A  cluster  of  tolerable  richness,  the  components 
ranging  from  mag.  8  to  12.  7|°  S.W.  of  y. 

13  W  VI.  (H.  4335.)  R.  A.,  i;h.  43m.  35$.;  Dec., 
—  30°  10.9'.  A  cluster  composed  principally  of  i2th  mag. 
stars.  A  curious  rift  in  the  middle.  3^°  nearly  due  W. 
(a  trifle  N.)  from  y. 

7  M.     (H.  4340.)     R.  A.,  i7h.  46m.  405.;  Dec.,— 34° 
47.2'.     A  cluster  of  stars  from  mag.  7  to  12.     Rich  but 
rather  straggling.     A  line  from  d  Scorp.  to  Antares,  and 
22^°  on,  will  pass  about  i°  S.  of  the  cluster. 

8  M.     (H.  4361.)     R.  A.,   iyh.  57m.   8s.;    Dec., -24° 
22.6'.     A  singular  and  splendid  nebula.      "  In   a   large 
field  we  find  a  bright  coarse  triple  star,  followed  by  a 
resolvable  luminous  mass,  including  two  stars  or  starry 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK.  153 

centres,  and  then  by  a  loose  bright  cluster  enclosed  by 
several  stars."  (Webb.)  Sir  J.  Herschel  remarks  that 
the  cluster  seems  to  be  superposed  upon  the  nebula. 
5f°  almost  exactly  N.  of  y. 

21  M.  (11.4367.)  R.A.,i7h.  5801.  2S.;  Dec.,-22° 30.8'. 
A  coarse  cluster  of  telescopic  stars  in  a  rich  galaxy  region. 
i|°  due  N.  of  last  object. 

3729  h.  (H.  4376.)  R.  A.,  i8h.  om.  36s.;  Dec.,-23° 
14'.  A  large  rich  cluster.  2^°  S.W.  of  //'. 

30  W  VII.  (H.  4388.)  R.  A.,  i8h.  6m.  8s.;  Dec., 
—  21°  35.8'.  "A  curious  large  undefined  cloud  of  loth 
mag.  stars,  requiring  low  power  and  steady  gazing." 
(Webb.)  |  S.W.  of  p\ 


SCORPIO  (THE  SCORPION). 

A  superb  constellation,  the  most  brilliant  of  the 
Southern  asterisms  that  are  visible  in  our  latitudes. 
Mean  R.  A.,  i6h.  355.;  Dec.,  — 33°  ;  stars,  200. 

a.  (Antares.)  R.  A.,  i6h.  22m.  398.;  Dec.,  — 26°  11.2'. 
A  splendid  star  of  mag.  i,  of  a  fiery  red  color.  "  It  is  a 
grand  telescopic  object.  Its  tint,  however,  is  not  uniform. 
To  me  the  disc  appears  yellow,  with  flashes  of  deep  crim- 
son, alternating  with  a  less  proportion  of  fine  green." 
(Webb.)  It  has  a  minute  green  companion  of  mag.  7, 
D.,  3.02",  which  is  a  noted  and  severe  test.  It  has  been 
seen  by  Warner  with  2f  inches,  but  Proctor  doubts  whether 
anything  under  four  inches  may  be  expected  to  show  it. 
The  possessor  of  a  3-inch  may  try  it  under  favorable 
atmospheric  conditions,  especially  if  he  happens  to  live 
S.  of  latitude  40°. 


154  THE    AMATEUR    TELESCOPIST  S    HANDBOOK. 

/?.  (Acrab.)  R.  A.,  i5h.  59111.  25.;  Dec.,  — 19°  30.2'. 
A  fine  double.  A  2,  pale  white  ;  B  5^,  lilac  tinge.  D., 

•3.5" 

v.  R.  A.,  i6h.  5m.  365.;  Dec.,— 19°  10.3'.  A  multiple 
star ;  double  in  a  small  telescope.  A  4,  bright  white  ; 
B  7,  pale  lilac.  D.,  40.8".  if0  E.  and  a  little  N.  from  ft. 

So  M.  (H.  4173.)  R.  A.,  i6h.  iom.  263.;  Dec.,-22° 
43.2'.  A  compressed  globular  cluster  of  extremely  minute 
stars.  It  has  a  nebulous  or  cometary  aspect.  Sir  W. 
Herschel  called  it  the  richest  and  most  condensed  mass  of 
stars  which  the  firmament  can  offer  to  the  contemplation 
of  astronomers  ;  a  description  which  the  worker  with  a 
small  telescope  will  hardly  appreciate.  Near  its  centre, 
but  probably  between  us  and  it,  is  the  variable  T,  which 
in  1860  had  risen  to  the  7th  magnitude,  entirely  over- 
powering the  cluster,  but  in  less  than  a  month  faded  out, 
and  has  not  (1893)  been  seen  distinctly  since.  Exactly 
midway  between  a  and  ft. 

4  M.  (R  4183.)  R.  A.,  i6h.  i6m.  535.;  Dec., -26° 
14.8'.  A  pale,  elongated  cluster,  nebulous  in  small  tele- 
scopes, about  2.5'  long,  and  brightening  towards  the  cen- 
tre. i|°  W.  of  Antares  ;  i°  S.  a  trifle  E.  from  <?. 

62  M.  (H.  4261.)  R.  A.,  i6h.  54m.  145.;  Dec.,  — 29° 
55.4'.  A  fine  resolvable  nebula,  brightening  towards  the 
centre.  Line  from  a  to  a  and  8|°  on. 

SCUTUM  SOBIESKI.     See  CLYPEUS  SOBIESKI. 

SERPENS  (THE  SERPENT). 

A  long  winding  constellation  of  little  interest  ;  really  a 
part  of  Ophiucus.  Mean  R.  A.,  i6h.  4501.;  Dec.,  o°  ; 
stars,  187. 


THE    AMATEUR    TELESCOPIST  S    HANDBOOK.  155 

6.  R.  A.,  i8h.  50111.  455.;  Dec.,  +  4°  3.4'.  A  beautiful 
double.  A  4^,  pale  yellow  ;  B  5,  golden  yellow.  D. 
21.6".  A  noble  pair.  It  lies  i|°  S.  of  a  line  from  d 
Aquilae  to  a  Ophiuci,  and  7^°  from  8  Aq. 

72  ]£  VIII.  (H.  4410.)  R.  A.  (1880),  i8h.  22m.; 
Dec.,  +  6°  29'.  A  very  fine  cluster  of  small  stars.  "  Be- 
tween it  and  6,  nearer  the  former,  is  a  beautiful  large  cloud 
of  stars,  chiefly  8  and  9  mag. ,  a  nearer  part,  apparently, 
of  the  Galaxy  ;  visible  to  naked  eye,  and  requiring  a  large 
field."  (Webb.)  7°  from  6,  almost  on  a  line  (a  trifle  S.) 
from  6  to  a  Oph.  a  Here,  and  a  Oph.  point  almost  to  it. 


SEXTANS  (THE  SEXTANT). 

A  small  and  unimportant  asterism  formed  by  Hevelius. 
Mean  R.  A.,  9h.  56m.;  Dec.  +  2°  ;  stars,  112. 

163  1£I  I.  (H.  2008.)  R.  A.,  9h.  59m.  455.;  Dec.,  -  7° 
11.3'.  An  elongated  bright  nebula  which  is  possibly  vari- 
able, since  Sir  J.  Herschel  could  scarcely  see  it  with  six 
inches  of  his  2o-foot  reflector,  while  it  is  now  readily  visi- 
ble, and  bears  magnifying  unusually  well,  in  a  2^-inch  re- 
fractor. Extend  a  line  9^°  due  E.  from  a  Hydrae  ;  and 
from  this  point,  a  line  i^°  due  N. 


TAURUS  (THE  BULL). 

A  brilliant  and  beautiful  constellation,  of  the  highest 
interest  both  to  the  naked  eye  and  the  telescope.  Mean 
R.  A.,  4h.  3m.;  Dec.,  +  16°  ;  stars,  394. 

a.  (Aldebaran.)  R.  A.,  4h.  29m.  363.;  Dec,  +  16° 
17.5'.  A  noble  red  star,  pale  rose  tint,  with  a  blue  tele- 


156  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

scopic  companion.  D.,  113.9".  The  companion  is  a  dif- 
ficult object,  but  a  3j-inch  will  show  it. 

01  B\  R.  A.,  4h.  22m.  i6s.;  Dec.,  +  15°  43.1'.  A 
beautiful  wide  pair.  A  5,  pearly  white  ;  B  51,  yellowish. 
D.,  337.3".  These  stars  are  next  to  a  in  the  V  that  marks 
the  Hyades. 

x1  H\  R.  A.,  4h.  i8m.  385.;  Dec.,  +  22°  2.5'.  A  fine 
wide  pair.  A  5^,  yellowish  white  ;  B  6J,  white.  D.,  339". 
7°  from  a  just  E.  of  a  line  from  a  to  £  Pers. 

r.  R.  A.,  4h.  35m.  385.;  Dec.,  +  22°  44.8'.  A  star 
with  rather  distant  companion.  A  5,  bluish  white  ;  B  8, 
lilac.  D.,  63.3".  7°  from  a  on  line  to  Capella. 

q>.  R.  A.,  4h.  13111.  343.;  Dec.,  -f  27°  5.4'.  A  beauti- 
ful wide  double.  A  6,  light  red  ;  B  8J,  cerulean  blue. 
D.,  53.7".  A  red  7th  mag.  star  follows  it  by  15'.  i2°*from 
a  on  line  to  a  Pers. 

X.  R.  A.,  4h.  1501.  535.;  Dec.,  +  25°  22.2'.  A  pretty 
double.  A  6,  white  ;  B  8,  pale  blue.  D.,  19.2".  2°  S.  a 
trifle  E.  from  cp. 

62.  R.  A.,  4h.  1 7m.  225.;  Dec.,  -f  24°  2.8'.  A  pretty 
double.  A  7,  silver  white  ;  B  8J,  purple.  D.,  28.9".  In 
a  fine  field.  The  last  two  objects  point  directly  to  it,  x  ly- 
ing almost  midway  between  cp  and  62. 

118.  R.  A.,  5h.  22m.  305.;  Dec.,  +  25°  3.6'.  An  ele- 
gant double.  A  7,  white  ;  B  7^,  pale  blue.  D.,  5.1". 
3°  from  ft,  a  trifle  W.  of  a  line  from  fi  to  £. 

257  P.  IV.  R.  A.,  4h.  52m.  445.;  Dec.,  +  14°  22.5'. 
A  beautiful  wide  triple.  A  7,  white  ;  B  8,  cerulean  blue  ; 
C  10,  purple.  D.,  AB  39",  AC  54.2".  Line  from  Betel- 
geuse  through  the  triangle  of  Orion's  head  and  ioj°  on. 

548  ^.  R.  A.  (1880),  4h.  2im.;  Dec.,  +  30°  6'.  A 
pretty  double.  A  6,  yellowish  ;  B  8,  bluish.  D.,  14.2". 
8°  from  r,  on  line  to  a  Pers. 


THE    AMATEUR    TELESCOPIST  S   HANDBOOK.  157 

785  2.  R.  A.  (1880),  sh.  39m.;  Dec.,  f  25°  53'.  A 
pretty  double.  A  6J,  white  ;  B  7$,  bluish  white.  D., 
13.8".  5°  from  /?,  a  trifle  E.  from  a  line  from  ft  to  rf 
Gemin. 

4  ]£  VII.  (H.  1030.)  R.  A.,  50.  5m.  428.;  Dec., 
+  1 6°  34.1'.  A  very  rich  cluster  of  small  stars,  more  than 
filling  the  field.  8J-0  from  a  on  line  to  y  Gemin. 

i  M.  (H.  1157.)  R.  A.,  5h.  27m.  515.;  Dec.,  +  21° 
56.6'.  A  pearly  white  nebula,  the  famous  "  Crab  Nebula  " 
of  Lord  Rosse,  and  notable  as  the  object  the  accidental 
discovery  of  which  by  M.  Messier  in  1758  led  to  the  forma- 
tion by  him  of  the  first  catalogue  of  nebulae.  It  is  of  an 
oval  form,  and  bears  some  resemblance  to  a  telescopic 
comet,  for  which  it  has  more  than  once  been  mistaken. 
i^°  from  8,  on  line  to  2,  Pers. 

THE  PLEIADES.  Mean  R.  A.,  3h.  38m.;  Dec.,  4-  23° 
30'.  This  famous  and  most  beautiful  group  of  stars  forms 
a  glorious  low-power  field.  Tempel's  Nebula,  a  faint  tri- 
angular haze  involving  Merope,  the  star  s p  Alcyone  the 
brightest  of  the  group,  should  be  looked  for,  as  it  has  been 
seen  with  less  than  2  inches.  It  is  suspected,  with  good 
reason,  of  variability. 

THE  HYADES.  Mean  R.  A.,  4h.  2om.;  Dec.,  +  15°. 
This  group  gives  several  fine  low-power  fields.  It  is  about 
2°  W.  and  a  little  S.  of  a. 


TRIANGULUM  (THE  TRIANGLE.) 

A  small  but  ancient  asterism.     Mean   R.  A.,  2h.   5m.; 
Dec.,  +  32°  ;  stars,  33. 

i.     R.  A.,  2h.    5m.  598.  ;   Dec.,  +  29°  47.2'.     A  most 
beautiful  double.     A  5 J- ,  topaz  yellow  ;  B  7,  green.     D., 


158  THE    AMATEUR    TELESCOPIST's    HANDBOOK. 

3.86".  Colors  very  fine.  Line  from  y  Androm.  to  ft 
Triang.  and  4j°  on. 

28  B.  R.  A.,  2h.  8m.  175.;  Dec.,  +  29°  53.1'.  A  pretty 
double.  Both  8,  both  very  white.  D.,  6.41".  2m.  i8s. 
E.  of  z,  and  6'  towards  the  N. 

33  M.  (H.  352.)  R.  A.,  ih.  27m.  385.;  Dec.,  4-  30° 
6.8'.  A  large  faint  nebula,  only  visible  with  low  powers. 
It  is  about  30'  in  diameter.  One  of  the  Rosse  "  spirals." 
Line  from  e  Pers.  to  /?  Triang.  and  8^-°  on. 


URSA  MAJOR  (THE  GREATER  BEAR). 

A  grand  constellation,  one  of  the  noblest  of  them  all. 
Mean  R.  A.,  loh.  38m.;  Dec.,  +  56°  ;  stars,  338. 

a.  (Dubhe.)  R.  A.,  loh.  56m.  563.;  Dec.,  +  62°  20.7'. 
A  bright  star  with  a  very  distant  companion.  A  i  J,  yel- 
low ;  B  8,  yellow  (violet,  Webb).  D.,  380.6". 

ft.  (Merak.)  R.  A.,  loh.  55m.  125.;  Dec.,  +  56°  58.3'. 
A  star  with  a  very  distant  and  difficult  companion.  A  2, 
greenish  white  ;  B  n,  pale  gray.  D.,  245."  Others  in 
field. 

d.  (Megrez.)  R.  A.,  i2h.  9111.585.;  Dec.,  +  57°  38.6'. 
A  fine  star  with  a  distant  companion.  A  3,  pale  yellow  ; 
B  9,  ash-colored.  A  is  suspected  of  being  variable  between 
mag.  2  and  4  at  a  very  long  period.  D.,  188. 6". 

£.  (Mizar.)  R.  A.,  13!!.  i9m.  295.;  Dec.,  +  55°  30.1'. 
A  splendid  double.  A  3,  brilliant  white  ;  B  5,  pale  emer- 
ald. D.,  14.57."  Alcor,  a  5th  mag.  star  n^'  from  Mizar, 
forms  with  it  a  naked-eye  double. 

57.     R.  A.,  nh.  23m.  95.;  Dec.,  +  39°  56.5'.     A  beau- 


THE    AMATEUR    TELESCOPIST'S    HANDBOOK.  159 

tiful  double.  A  6,  lucid  white  ;  B  9,  violet.  D.,  5.43". 
7^°  from  v,  a  trifle  E.  of  line  from  v  to  d. 

1402  2.  R.  A.,  9h.  57m.  315.;  Dec.,  +  56°  0.8'.  A 
pretty  double.  A  y£,  yellow ;  B  8J,  bluish.  D.,  23.5". 
6°  from  6  on  line  to  ft. 

1603  2.  R.  A.,  i2h.  2m.  385.;  Dec.,  +  56°  5'.  A  neat 
double.  A  yj,  B  8,  both  white.  D.,  22.4".  About  mid- 
way between  y  and  d. 

205  1$  I.  (H.  1823.)  R.  A.,  9h.  1401.  245.;  Dec.,  + 
51°  28.1'.  An  elliptical  nebula  about  4'  long,  a  miniature 
of  the  great  Andromeda  nebula.  It  is  pale  white,  and 
nucleated.  2°  from  6  on  line  to  i. 

78  13  I.  (H.  1909.)  R.  A.,  9h.  4om.  325.;  Dec.,  + 
7  2°  47. 7'.  Around  nebula.  Line  from  £  to  A.  and  9° 
on. 

81  and  82  M.  (H.  1949,  1950.)  Mean  R.  A.,  9!!.  46m. 
235.;  Dec.,  +  69°  38.8'.  The  first  of  these  is  oval.  The 
other  is  J°  S.  of  81,  and  is  long  and  narrow.  T;  and  £ 
point  to  them.  27°  from  £. 

286  !£  I.  (H.  1982.)  R.  A.,  9h.  53m.  365.;  Dec., 
+  69°  16.3'.  A  round  lucid  white  nebula,  brightening 
towards  centre.  "  There  are  two  lines  of  three  stars  each 
across  the  field,  of  which  the  one  preceding  the  nebula  is 
of  the  7th  mag.  and  that  following  of  the  loth  ;  between 
these  the  sky  is  intensely  black,  and  shows  the  nebula  as 
if  floating  in  awful  and  illimitable  space,  at  an  inconceiv- 
able distance."  if0  E.  and  £°  N.  of  last  object. 

46  l£  V.  (H.  2318.)  R.  A.,  nh.  4m.  595.;  Dec.,  + 
56°  15.6'.  A  faint  but  large  and  well-defined  elon- 
gated curved  nebula.  About  ij°  from  /?  nearly  on  line 
to  y. 

97  M.  (H.  2343.)  R.  A.,  nh.  8m.  i9s.;  Dec.,  +  55° 
36.7'.  A  wonderful  planetary  nebula,  large  and  pale, 


l6o  THE    AMATEUR    TELESCOPIST'S    HANDBOOK. 

about  2  40"  in  diameter.  If  this  nebula  were  only  as  dis- 
tant from  us  as  6 1  Cygni,  its  real  diameter  would  be  seven 
times  that  of  the  orbit  of  Neptune  ;  but  as  its  distance 
was  actually  beyond  the  gauging  powers  of  Herschel's 
2o-foot  reflector,  it  must  be,  according  to  Sir  William's 
estimate,  at  least  of  the  pSoth  order  ;  in  other  words,  980 
times  the  distance  of  Sirius  !  Its  actual  dimensions  must 
be,  then,  of  a  character  that,  in  Admiral  Smyth's  phrase, 
makes  the  imagination  quail  Less  than  i°  S.E.  of  last 
object. 

J73  W  I-  (H.  2600.)  R.  A.,  nh.  47m.  125. ;  Dec.,  + 
37°  36.2'.  A  pale  white  nebula,  brightening  towards  the 
middle,  of  considerable  size.  Line  from  Polaris  to  y  and 
17°  on  ;  then  a  trifle  E. 

43  ¥  V.  (2841.)  R.  A.,  i2h.  i3m.  335.;  Dec.,  +  47° 
54.5'.  A  white  oval  nebula,  better  denned  at  edges  than 
at  ends.  It  has  a  nucleus  in  its  southern  portion.  Line 
from  a  to  y,  and  yj0  on. 


URSA  MINOR  (THE  LESSER  BEAR). 

A  small,  but,  from  its  position,  highly  important 
constellation.  Mean  R.  A.,  15!!.  pm.;  Dec.,  +  79°  ; 
stars,  75. 

a.  (Polaris.)  R.  A.,  ih.  i8m.  145.;  Dec.,  +  88°  43.3'. 
The  Pole-Star,  the  most  important  of  all  the  stars  to  the 
inhabitants  of  our  planet.  It  is  a  noted  double.  A  2j, 
topaz  yellow  ;  B  9^,  pale  white.  D.,  18.5".  This  is  a  well- 
known  test.  It  has  been  seen  by  some  observers  with  as 
low  as  one  inch,  but  Dawes  suggests,  that,  as  a  general  rule, 
a  good  2-inch  and  a  good  eye  should  detect  the  little  star 


THE    AMATEUR    TELESCOPIST's    HANDBOOK.  l6l 

with  the  power  of  80.     The  smallest  aid  that  shows  it  to 
me  is  2 £  inches  with  a  power  of  64. 


VIRGO  (THE  VIRGIN). 

A  noble  constellation  of  great  dimensions,  and  replete 
with  astronomical  interest.  Mean  R.  A.,  13!!.  i6m.;  Dec., 
—  2°  30';  stars,  411. 

a.  (Spica.)  R.  A.,  13!!.  igm.  245.;  Dec.,— 10°  35.2'. 
A  beautiful  bright  star  with  a  distant  telescopic  com- 
panion. A  i,  brilliant  flushed  white  ;  B  10,  bluish  tinge. 
D,  359-8". 

y.  R.  A.,  i2h.  36m.  55.;  Dec.,  — o°  50.8'.  A  splendid 
and  famous  binary  with  a  period  of  about  180  years.  Both 
4,  both  yellowish.  D.  (1880),  5.24".  This  noble  pair 
appeared  single  to  all  but  the  most  powerful  telescopes 
in  1836,  and  has  been  widening  ever  since. 

S.  R.  A.  (1880),  i3h.  27m.;  Dec.,-6°  35'.  A  vivid 
red  variable,  ranging  in  374  days  from  mag.  7 J  to  i2j. 
It  is  said  to  show  especially  a  feature  of  several  vari- 
ables, a  striking  twinkling  at  times,  particularly  on  the 
point  of  diminution.  (Webb.)  4§ °  from  Spica  on  line  to 
Arcturus. 

32  P.  XII.  R.  A.,  i2h.  i2m.  305.;  Dec.,— 3°  20.5'.  A 
fine  double.  Both  7^  (though  some  observers  rate  them 
as  differing  by  half  a  magnitude),  and  both  white.  D., 
20.1".  3^°  from  rj  on  line  to  e  Corvi. 

196  P.  XII.  R.  A.,  i2h.  45m.  395.;  Dec.,  — 9°  44.4'.  A 
very  pretty  double.  A  6J,  topaz  yellow  ;  B  9^,  lucid  pur- 
ple. D.  32.3".  6|°  from  d  on  line  to  d  Corvi. 

221  P.  XII.  R.  A.,  i2h.  49m.  595.;  Dec.,  +  12°  5.7'. 
ii 


162  THE    AMATEUR    TELESCOPIST's   HANDBOOK. 

A  neat  double.  A  yj,  pale  white  ;  B  9,  sky  blue  (reddish, 
Sadler).  D.,  29.  i".  2°  W.  a  trifle  N.  from  e. 

25  P.  XIII.  R.  A,  i3h.  9m.  us.;  Dec.,-  10°  46,4'. 
A  pretty  though  wide  double.  A  7^,  B  8J,  both  bluish. 
D.,  42.4".  2^°  W.  of  a. 

88  M.  (H.  3049.)  R.  A.,  i2h.  26m.  265.;  Dec.,  + 
15°  1.9'.  A  long  elliptical  nebula,  y'x  ij'  in  size.  Line 
from  a  to  6  and  i2j°  on.  "This  is  a  wonderfully  nebu- 
lous region,  and  the  diffused  matter  occupies  an  extensive 
space,  in  which  several  of  the  finest  objects  of  Messier 
and  the  Herschels  will  readily  be  picked  up  by  the  keen 
observer  in  extraordinary  proximity.  It  will  be  conven- 
ient to  keep  in  mind  that  the  situation  of  the  extraordinary 
conglomerate  of  nebulae  and  compressed  spherical  clusters 
which  crowd  the  Virgin's  left  wing  and  shoulder  is  pretty 
well  pointed  out  to  the  practised  naked  eye  by  £,  d,  y,  rj 
and  ft  Virg.  forming  a  semicircle  to  the  E.,  whilst  due  N. 
of  the  last-mentioned  star,  ft  Leonis  marks  the  N.W. 
boundary.  Reasoning  upon  the  Herschelian  principle, 
this  may  reverently  be  assumed  as  the  thinnest  or  shallow- 
est part  of  our  firmament,  and  the  vast  laboratory  of  the 
segregating  mechanism  by  which  compression  and  insula- 
tion are  ripened  in  the  course  of  unfathomable  ages.  The 
theme,  however  imaginative,  is  solemn  and  sublime." 
(Smyth.) 

98  M.  (H.  2786.)  R.  A.,  i2h.  8m.  345.;  Dec.,  +  15° 
30.5'  A  faint  and  pale  elongated  nebula.  6^°  nearly  due 
E.  (a  trifle  N.)  from  ft  Leonis. 

87  M.  (H.  3035.)  R.  A.,  i2h.  25m.  155.;  Dec.,  +  12° 
59.4'.  A  large,  round  nebula,  brighter  at  centre,  8^° 
from  s  on  line  to  ft  Leonis. 

31  J$  I.  (H.  3075.)  R.  A.,  i2h.  28m.  285.;  Dec.,  + 
8°  18.1'.  An  extended  nebula  much  brighter  in  centre. 


THE   AMATEUR    TELESCOPIST's   HANDBOOK.  163 

Line  from  a  to  6  and  15^°  on.  There  is  splendid  sweep- 
ing with  a  low  power  all  through  this  nebulous  region  ; 
but  identification  is  very  difficult,  and  only  a  few  typical 
nebulae  have  been  here  described. 


BENEDICITE  OMNI  A   OPERA  DOMINI   DOMINO  ; 
BENEDICITE   SOL   ET   LUNA   DOMINO  ; 
BENEDICITE   STELLA   CCELI   DOMINO  ; 
LAUDATE  ET   SUPEREXALTATE  BUM  IN   SPECULA. 


LONGMANS,  GREEN,  &•>  CO.'S  PUBLICATIONS. 

CELESTIAL  OBJECTS  FOR  COMMON  TELESCOPES. 

By  the  Rev.  T.  W.  WEBB,  M.A.,  F.R.A.S.  Fifth  Edition.  Revised  and 
greatly  enlarged  by  Rev.  T.  E.  EsPJN,  M.A.,  F.R.A.S.  In  Two 

Volumes. 

Vol.  I.  The  Instrument  and  the  Observer.  With  Notes  on  Celestial  Photog- 
raphy and  on  the  Spectroscope  applied  to  the  Telescope — The  Solar 
System.  With  Portrait  of  the  Author.  Map  of  the  Moon  and  Chart 
of  Mars,  and  other  illustrations.  Crown  8vo.  $1.75. 

Vol.  II.  [In  immediate  preparation. 

HOURS  WITH  A  THREE-INCH  TELESCOPE. 

By  CAPTAIN  WILLIAM  NOBLE,  F.R.A.S.,  etc.  With  a  Map  of  the  Moon 
and  105  Illustrations.  Crown  8vo.  $1.50. 

OUTLINES  OF  ASTRONOMY. 

By  SIR  J.  F.  W.  HERSCHEL,  Bart.,  M.A.  With  Plates  and  Diagrams. 
8vo.  $4.00. 

ELEMENTS  OF  ASTRONOMY. 

By  SIR  R.  S.  BALL,  LL.D.,  F.R.S.,  Andrews  Professor  of  Astronomy  in 
the  University  of  Dublin,  Royal  Astronomer  of  Ireland.  With  136 
Woodcuts.  I2mo.  $2.00. 

THE  MILKY  WAY.    From  the  North  Pole  to  10°  of  South  Declination. 

Drawn  at  the  Earl  of  Rosse's  Observatory  at  Birr  Castle. 
By   OTTO    BOEDDICKER.     With   Descriptive   Letterpress.     4   Plates,    size 

18x23  inches,  in  portfolio.     $10.00. 

"  The  result  is  certainly  by  far  the  most  beautiful  and  detailed  representations  of  the 
Milky  Way  that  has  ever  been  produced." — -Journalofthe  British  Astronomical  Association. 

THE  SYSTEM  OF  THE  STARS. 

By  AGNES  M.  CLERKE,  Author  of  "A  History  of  Astronomy  during  the 
Nineteenth  Century."  With  6  Plates  and  Numerous  Illustrations. 
8vo.  $7.00. 

LONGMANS,  GREEN,  &  CO.,  15  East  Sixteenth  St.,  New  York. 


LONGMANS,   GREEN,  &  CO.'S  PUBLICATIONS. 

OPTICAL  PROJECTION  :    A  Treatise  on  the  Use  of  the  Lantern  in 

Exhibition  and  Scientific  Demonstration. 
By  LEWIS  WRIGHT,  Author  of  "  Light  :  a  Course  of  Experimental  Optics." 

With  232  Illustrations.     I2mo.     $2.25. 

A  TREATISE  ON  PHOTOGRAPHY. 

By  CAPTAIN  W.  DE  WIVELESLIE  ABNEY,  F.R.S.,  late  Instructor  in 
Chemistry  and  Photography  at  the  School  of  Military  Engineering, 
Chatham.  Sixth  Edition.  With  Chapters  on  Celestial  Photography  and 
Photography  with  the  Microscope.  With  115  Woodcuts.  121110.  $1.25. 

PRACTICAL  PHYSICS. 

By  R.  T.  GLAZEBROOK,  M.Ai,  F.R.S.,  and  W.  N.  SHAW,  M.A.,  Demon- 
strators at  the  Cavendish  Laboratory,  Cambridge.  With  Woodcuts. 
Fourth  Edition.  Revised  and  Enlarged.  Crown  8vo.  $2.50. 

PHYSICAL  OPTICS. 

By  R.  T.  GLAZEBROOK,  M.A.,  F.R.S.,  Fellow  and  Lecturer  of  Trinity 
College  ;  Demonstrator  of  Physics  at  the  Cavendish  Laboratory,  Cam- 
bridge. With  183  Woodcuts  of  Apparatus,  etc.  I2mo.  $2.00. 

PHYSIOGRAPHY. 

With  180  Illustrations,  6  Maps,  and  a  Colored  Plate  of  Spectra.  (LONG- 
MANS' ADVANCED  SCIENCE  MANUALS.)  Crown  8vo.  $1.40. 

Contents. — I.  The  Celestial  Sphere — Constellations  —  Definitions  and 
Explanations.  II.  General  Survey  of  the  Solar  System.  III.  Light  and 
Astronomical  Instruments.  IV.  Spectrum  Analysis.  V.  The  Physical  and 
Chemical  Constitution  of  the  Sun.  VI.  Description  of  the  Planets.  VII. 
The  Moon — Its  Dimensions — Orbit — Rotation — Phases,  Physical  Condi- 
tions—Eclipses. VIII.  The  Tides.  IX.  Comets  and  Meteors.  X.  The 
Motions  of  the  Earth — Changes  in  the  Orbit.  XL  Measurement  of  the 
Surface,  Size,  and  Shape  of  the  Earth — Mass  of  the  Earth — Determination 
of  Latitude  and  Longitude.  XII.  Celestial  Measurements.  XIII.  Gravita- 
tion and  Celestial  Masses.  XIV.  Stars  and  Nebulae.  XV.  Atmospheric 
and  Oceanic  Movements.  XVI.  Terrestrial  Magnetism.  XVII.  Cosmog- 
ony— Secular  Cooling  of  the  Earth — Secular  Changes  of  Climate.  Appendix: 
The  Greek  Alphabet — Time  Constants — Trigonometrical  Functions — Prin- 
cipal Elements  of  the  Solar  System  —  The  Transit  Circle  —  Geological 
Importance  of  Tides — Age  of  the  Earth — Geological  Chemistry. 


LONGMANS,  GREEN,  &  CO.,  15  East  Sixteenth  St.,  New  York. 


LONGMANS,   GREEN,  &  CO.'S  PUBLICATIONS. 

OLD  AND   NEW  ASTRONOMY. 

By  RICHARD  A.  PROCTOR,  author  of  "Astronomy"  in  the  Encyclopaedia 
Britannica  and  in  the  American  Cyclopaedia ;  and  A.  COWPER 
RANYARD.  With  31  Plates  and  472  Woodcuts,  etc.,  in  the  Text. 
4to.  824  pages.  $12.00. 

The  publication  of  the  "  Old  and  New  Astronomy  "  was  announced  in 
1887,  and  the  First  Part  was  published  in  March,  1888.  At  the  date  of  Mr. 
Proctor s  death,  in  September,  1888,  Part  VI.  had  been  issued  and  Part  VII. 
was  in  type.  The  chapters  on  the  Planets  were  in  manuscript,  and  appeared 
to  be  nearly  ready  for  publication;  but,  as  they  had  been  written  at  Mr. 
Proctor's  home  in  Florida,  where  he  was  at  a  distance  from  libraries,  more 
work  was  required  to  complete  them  than  Mr.  Ranyard  expected  when  he 
undertook  to  finish  the  volume.  The  manuscript,  as  far  as  it  went,  ended 
with  the  description  of  the  discovery  of  Neptune,  the  outermost  member  of 
the  solar  system.  Unfortunately,  Mr.  Proctor  had  written  nothing  with 
regard  to  the  Universe  of  Stars,  the  Distribution  of  Nebulae,  and  the  Con- 
struction of  the  Milky  Way,  though  it  was  known  that  he  intended  to  make 
these  sections  a  special  feature  of  the  book. 

It  was  in  this  department  of  Astronomy  that  he  had  done  his  most 
original  and  lasting  work,  work  by  which  his  name  will  probably  be  long 
remembered  ;  but  it  was  left  for  his  friends  to  compare  it  with  what  had 
been  accomplished  by  others.  Mr.  Ranyard  has  therefore  endeavored,  in 
the  Stellar  section  of  the  "Old  and  New  Astronomy,"  to  give  as  complete 
a  review  as  he  could  of  the  various  theories  which  have  been  advocated  with 
regard  to  the  Milky  Way  and  the  distribution  of  Stars  and  Nebulae. 

In  discussing  the  distribution  of  matter  in  the  space  around  us,  and 
other  problems  of  the  New  Astronomy,  Mr.  Ranyard  has  avoided  making 
use  of  data  which  depend  upon  observations  bordering  on  the  limit  of 
visibility,  such  as  the  parallax  of  any  but  the  nearest  stars,  or  the  motion  of 
stars  in  the  line  of  sight,  with  regard  to  which  there  is  still  considerable 
uncertainty  and  a  wide  difference  in  the  results  obtained  by  different 
observers.  The  photo-metric  observations,  the  stellar  photographs,  and 
observations  of  proper  motions,  and  stellar  distribution,  which  have  been 
made  use  of,  afford  a  much  surer  foundation  for  cosmical  deductions. 

CONTENTS : 


Introduction. 

1.  Ancient   and    Modern   Methods   of 

Observing  the  Heavenly  Bodies. 

2.  Ancient  and  Modern  Studies  of  the 

Earth's  Shape. 

3.  Apparent  Motions  of  the  Sun,  Moon 

and  Planets. 

4.  The  True  Mechanism  of  the  Solar 

System. 

5.  Measuring  and  Weighing  the  Solar 

System. 

6.  The  Sun. 

7.  The  Sun's  Surroundings. 


CHAP. 

8.  The  Inferior  Planets. 

9.  The  Planet  Earth. 

10.  The  Moon  as  a  Planet. 

11.  The  Planet  Mars. 

12.  The  Zone  of  Asteroids. 

13.  The  Planet  Jupiter. 

14.  The  Planet  Saturn. 


Ji: 


The  Planet  Uranus. 
The  Planet  Neptune. 


17.  The  Stars. 

Table  of  Astronomical  Constants. 
Index. 


LONGMANS,  GREEN,  &  CO.,  15  East  Sixteenth  St.,  New  York. 


LONGMANS,   GREEN,  <&»  CO.'S  PUBLICATIONS. 


WORKS     BY    RICHARD    A.     PROCTOR. 


OLD  AND  NEW  ASTRONOMY. 

By  RICHARD  A.  PROCTOR  and  A.  COWPER  RANYARD.     With  31  Plates  and 
472  Woodcuts,  etc.,  in  the  Text.     4to.     824  pages.     $12.00. 


The  Moon  :  Her  Motions,  Aspect, 
Scenery,  and  Physical  Condition. 
With  many  Plates  and  Charts, 
W7ood  Engraving,  and  2  Lunar 
Photographs.  Crown  8vo.  $2.00. 

The  Universe  of  Stars:  Re- 
searches into,  and  New  Views 
respecting,  the  Constitution  of  the 
Heavens.  With  22  Charts  (4  col- 
ored) and  22  Diagrams.  8vo.  $3- 50. 

Other  Worlds  than  Ours:    The 

Plurality  of  Worlds  Studied  under 
the  Light  of  Recent  Scientific 
Researches,  With  14  illustrations, 
Maps,  Charts,  etc.  Cr.  8vo.  $1.25. 

Treatise  on  the  Cycloid  and  all 
Forms  of  Cycloidal  Curves,  and 

on  the  Use  of  Cycloidal  Curves 
in  dealing  with  the  Motions  of 
Planets,  Comets,  etc.  With  161 
Diagrams.  Crown  8vo.  $3-75- 

The  Orbs  Around  Us  :  Essays  on 
the  Moon  and  Planets,  Meteors 
and  Comets,  the  Sun,  and  Colored 
Pairs  of  Suns.  Crown  8vo.  $1.25. 

Light  Science  for  Leisure 
Hours:  Familiar  Essays  on 
Scientific  Subjects,  Natural  Phe- 
nomena, etc.  3  vols.  Crown 
8vo.  $1.75  each. 

New  Star  Atlas  for  the  Library, 
the  School,  and  the  Observa- 
tory, in  Twelve  Circular  Maps 
(with  Two  Index-Plates).  With 
an  Introduction  on  the  Study  of 
the  Stars.  Illustrated  by  9  Dia- 
grams. Crown  8vo.  $1.75. 


(Larger)  Star  Atlas  for  Observ- 
ers and  Students,  in  Twelve 
Circular  Maps,  showing  6,000 
Stars,  i,  500  Double  Stars,  Nebulse, 
etc.  With  Two  Index-Plates. 
Folio.  $6.00. 

Nature  Studies.  By  GRANT 
ALLEN,  A.  WILSON,  T.  FOSTER, 
Eo  CLODD,  and  R.  A.  PROCTOR. 
Crown  8vo.  $1.25. 

Rough  Ways    Made    Smooth. 

Familiar  Essays  on  Scientific  Sub- 
jects.    Crown  8vo.     $1.25. 

The  Expanse  of  Heaven  :  Essays 
on  the  Wonders  of  the  Firmament. 
Crown  8vo.  $1.25. 

Pleasant  Ways  in  Science. 
Crown  8vo.  $1.25. 

Myths  and  Marvels  of  Astron- 
omy. Crown  8vo.  $1.25. 

The  Student's  Atlas.  In  Twelve 
Circular  Maps  on  a  Uniform  Pro- 
jection and  one  Scale,  with  two 
Index  Maps.  Intended  as  a  vade 
mecum  for  the  Student  of  History, 
Travel,  Geography,  Geology,  and 
Political  Economy.  With  a  letter- 
press Introduction,  illustrated  by 
several  Cuts.  -  Crown  8vo.  $1.50. 

Lessons  in  Elementary  Astron- 
omy ;  with  Hints  for  Young  Tele- 
scopists.  With  47  Woodcuts. 
Fcp.  8vo.  60  cents. 

The  Great  Pyramid :  Observatory, 
Tomb  and  Temple.  Illustrated. 
Crown  8vo  $2.00. 


LONGMANS,  GREEN,  &  CO.,  15  East  Sixteenth  St.,  New  York. 


LONGMANS,   GREEN,  &>  CO.'S  PUBLICATIONS. 


TEXT-BOOKS  OF  SCIENCE. 


Photography.  By  CAPTAIN  W.  DE  WIVE- 
LESLIE  ABNEY,  F.R.S.  With  115  Wood- 
cuts. $1.25 

The  Strength  of  Materials  and  Struct- 
ures. By  SIR  J.  ANDERSON,  C.E., 
LL.D.,  F.R.S.E.  With  66  Woodcuts. 


Introduction  to  the  Study  of  Organic 
Chemistry  :  the  Chemistry  of  Carbon 
and  its  Compounds.  By  HENRY  E. 
ARMSTRONG,  Ph.D.,  F.R.S.  With  8 
Woodcuts.  $1.25 

Elements  of  Astronomy.  By  SIR  R.  S. 
BALL,  LL.D.,  F.R.S.  With  136  Wood- 
cuts. $2.00 

Railway  Appliances.  A  Description  of 
Details  of  Railway  Construction  subse- 
quent to  the  completion  of  Earthworks 
and  Structures.  By  JOHN  WOLFE 
BARRY,  M.I.C.E.  With  207  Woodcuts. 
$1-50 

Systematic  Mineralogy.  BY  HILARY 
BAUERMAN,  F.G.S.  With  373  Wood- 
cuts. $2.00 

Descriptive  Mineralogy.  By  HILARY 
BAUERMAN,  F.G.S.  With  236  Wood- 
cuts. $2.00 

Metals:  their  Properties  and  Treat- 
ment. By  C.  L.  BLOXAM  and  A.  K. 
HUNTINGTON.  With  130  Woodcuts. 


Practical    Physics.      By   R.   T.  GLAZE- 

BROOK,  M.A.,  F.R.S.,  and  W.  N.  SHAW 

M.A.  Fourth  Edition  (1893).    659  pages. 

$2.50 

Physical  Optics.  By  R.  T.  GLAZEBROOK, 

M.A.,    F.R.S.      With     183    Woodcuts. 

$2.00 

The  Art  of  Electro-Metallurgy,  includ- 
ing all  known  Processes  of  Electro-De- 
position. By  G.  GORE,  LL.D.,  F.R.S. 
With  56  Woodcuts.  $2.00 

Preliminary  Survey.  By  THEODORE 
GRAHAM  GRIBBLE,  Civil  Engineer. 
With  a  large  number  of  Illustrations, 
Quantity  Diagrams,  and  a  Manual  of 
the  Slide-rule.  440  pages.  $2.25 


The  Steam-Engine.  By  GEORGE  C.  V. 
HOLMES,  Whitworth  Scholar,  Secretary 
of  the  Institution  of  Naval  Architects. 
With  212  Woodcuts.  $2.00 

Electricity  and  Magnetism.  By  FLEE- 
MING  JENKINS,  F.R.SS.L.  &  E.  With 
177  Woodcuts.  $1.25 


Theory    of   Heat. 

WELL, 

Woodcuts. 


By    J.  CLERK    MAX- 
M.A.,    LL.D.  Edin.     With  41 


Introduction  to  the  Study  of  Inor- 
ganic Chemistry.  By  WILLIAM  AL- 
LEN MILLER,  M.D.,  LL.D.,  F.R.S. 

With  72  Woodcuts.  $1.25 

Telegraphy.  By  W.  H.  PREECE,  F.R.S., 
M.I.C.E.,  and  J.  SIVEWRIGHT,  M.A., 
C.M.G.  With  195  Illustrations.  $2.00 

The  Study  of  Rocks,  an  Elementary 
Text-Book  of  Petrology.  By  FRANK 
RUTLEY,  F.G.S.  With  6  Plates  and  88 
Woodcuts.  $1.50 

Workshop  Appliances,  including  De- 
scriptions of  some  of  the  Gauging  and 
Measuring  Instruments — Hand  Cutting 
Tools,  Lathes,  Drilling,  Planing,  and 
other  Machine  Tools  used  by  Engineers. 
By  C.  P.  B.  SHELLEY,  M.I.C.E.  With 
291  Woodcuts.  $1.50 

Qualitative  Chemical  Analysis  and 
Laboratory  Practice.  By  T.  E. 
THORPE,  Ph.D.,  F.R.S.,  and  M.  M. 
PATTISON  MUIR,  M.A.,  F.R.S.E.  With 
Plate  of  Spectra  and  57  Woodcuts. 
$1.25 

Introduction  to  the  Study  of  Chemical 
Philosophy  ;  the  Principles  of  Theo- 
retical and  Systematic  Chemistry.  By 
WILLIAM  A.  TILDEN,  D.Sc.  London, 
F.R.S.  With  Woodcuts.  $1.50 

Elements  of  Machine  Design.  By  W. 
CAWTHORNE  UNWIN,  B.Sc.,  M.I.C.E. 

Part  I.  General  Principles,  Fastenings, 
and  Transmissive  Machinery.  With  304 
Woodcuts.  $2.00 

Part  II.  Chiefly  Engine  Details. 
With  174  Woodcuts.  $1.50 


LONGMANS,  GREEN,  &  CO.,  15  East  Sixteenth  Street,  New  York. 


I  J.  V  JLJAViJ-I.  A   JL       V^J.       «  .  /-»  »  ,  •  i    «  »  i-v  i  -^  M  /-»      J_iiJL»A"Vr».A"V  X 

BERKELEY 


Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 


OtC    4 


D  LD    FEB19'6 
OCT291981 


«£C.CIR 


JUL2 


MAY  191955 


STACKS 


19689 


-12PM 


LD  21-100m-9,'47(A5702sl6)476 


701032 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


